No magazine will likely ever be the star addition to your gun collection. The magazine will never get an honorable mention in a war documentary. It’s just a small rectangular device we often take for granted as a necessary peripheral item that facilitates our shooting hobby. The detachable ammunition-feeding device should be more. It should be held in high regard—as something of great historical interest and significance. The development of the detachable magazine parallels the history and development of the small arm—as the modern repeating arm could not exist without its magazine.

History

In the interest of brevity, the internal box magazine common to bolt-action rifles, as well as the stripper clip, used to top off a fixed magazine and the aging single-stack magazine will only be discussed here in comparative reference. This is about the high capacity magazine: Man’s best attempts to provide the soldier and hobbyist with the most firepower he can hold in his two hands. To not wax political, there will be little mention here of any magazine that holds fewer than 11 rounds. As a general consideration, a high capacity magazine is one that is only limited in its size and capacity by the intent and functionality prescribed by that weapon’s designer, as any weapon must remain practical and convenient for the user of said weapon. Surely, the advent of the magazine as it is accepted today must be attributed to the military’s need for superior firepower. As warring forces sought to outdo one another, the infantry arm has always been at the forefront of the (literal) arms race. More power, more distance, higher fire rate and more ammo all equate to success and dominance over an opposing force. This endeavor continues with the military as well as modern law enforcement today. As it applies to the hobby shooter, we accept and uphold that it is our right as Americans to own and utilize our small arms for any and all lawful purposes. The practicality and utility of a high-capacity feeding device are not in question, nor can the importance and significance of the high cap mag be refuted.

The repeating arm became a viable weapon shortly after the invention of the self-contained cartridge in the late 1800s. Through the 1890s, firearm inventors began designing small arms around the detachable box magazine as we know it today—and as soon as it became established, it would quickly find broad success in pistol and submachine gun (SMG) designs of the day. Despite the obvious advantages of the detachable box, militaries around the world seemed to distrust or otherwise ignored the new technology as it applied to the full-powered infantry rifle. The stripper-fed internal box would remain the standard for the infantry rifle until the 1940s.

It has been well-demonstrated that a weapon’s magazine can make or break that particular weapon’s story of success on the battlefield. The famously miserable French Chauchat machine gun featured a magazine with large openings on the sides to provide the user with a visual indication of his remaining ammo supply. The short-sighted design also provided mud, dirt and vegetation an easy path into the gun’s mechanism. On the other hand, the British Sterling submachine gun has enjoyed a half century of distinguished service—renowned as one of the best small arms ever made. Some experts suggest it’s got much to do with the peerless design and craftsmanship of the magazine. The Sterling’s 34-round magazine is made of four welded strips of very thick high carbon steel. There’s a generous feed ramp built into the mag body where the cartridges exit. The follower consists of roller bearings that act as guides below the cartridges. And the follower is very tall—effectively what we might call “anti-tilt” today. Its inventor, George Patchett, saw the magazine less as a disposable sheet metal tube and more as a necessary and integral part of a complex mechanism—no less important than the stock, bolt or barrel.

From WWI though the 1950s we saw many variations and configurations of how the magazine interfaced with its host weapon. In the past, some would protrude vertically from the top of a gun while others extend out to the side. Today most magazines hang succinctly below the weapon. But the magazine’s orientation on the weapons of war was neither random nor arbitrary. These engineering decisions came from lessons learned in battle. WWI taught that when firing from cover, specifically from within a trench or behind a low barricade, a ventrally oriented 30+-round (long) magazine could interfere with the soldier’s ability to maintain safe cover and also confound the reloading of his weapon. In the vast mud puddle that was World-War-I France, it became evident that any opening on the belly of a weapon was a point of potential infiltration for debris. So the belief became widely adopted that a magazine needed to be located anywhere but the bottom of the action. Submachine guns like the Bergmann, Lanchester, Sten and Sterling had horizontally oriented magazines. The high-powered Johnson light machine gun (LMG) and the Fallshirmjagergewehr 42 would also feature horizontally arranged magazines protruding to the left of the action. In the case of the FG-42, it has been suggested that the magazine’s orientation would allow German paratroopers to more easily engage ground troops below while hanging from their parachute. Light machine guns like the BREN, Madsen, Japanese Type 96 and German MG15 had magazines that stood vertically from the surface of the receiver. The German MG15, as well as its near clone, the Japanese Type 98, were more commonly used with a double drum instead of the vertical box. The double drum, by placing the ammo directly to the sides of the gun, gave the user an unimpeded vision of the zone of fire. The Lewis gun and Russian Degtyaryov light machine guns were also fed from the top of the receiver but utilized flat drums with the ammo arranged around the drum like the pistons of a radial aircraft engine. This configuration provided better visibility than the vertically oriented magazine but introduced its own degree of complexity and a resultant potential for failure. These machine guns—with horizontal drums— were commonly mounted in early aircraft presumably due to the improved visibility and increased ammunition capacity afforded by this magazine type.

Belt-Fed

Where the high capacity box mag often fell short was its constant need to be replaced. Even the higher capacity drums—50, 75 or even 100 rounds—posed some logistical difficulties. As magazine capacity increased, so did the mechanism’s complexity and potential for failure. As battle tactics have changed over the past 100 years so has the role of the machine gun. A heavy machine gun may be asked to hold a position and perform area denial against advancing forces. This is the place and time for a belt-fed gun. The light machine gunner may be asked to advance, displace or relocate depending on the flow of the battle. The light machine gunner needs a more mobile and adaptable weapon. The ultimate result of the multi-role demand of the light machine gun was the Squad Automatic Weapon—a light machine gun that accepts belted ammo as well as detachable box or drum mags. Our M249, or generically the SAW, is that weapon. Other nations have resorted to hanging a hollow metal box on their belt-fed light machine gun. This belt box holds and protects a belt of linked ammo and allows for the LMG to be maneuvered and handled like a battle rifle. Belt boxes usually hold between 75 and 200 rounds of linked ammo. The RPD has been a very a successful LMG and notable example of this later configuration.

Feed Types

Essentially there are two ways to stack and store ammo in a magazine—single stack and staggered or nested. Single stack is just that. A single row of cartridges with mag body on either side, a follower below and feed lips above. The staggered magazine keeps two rows of ammo housed within the mag body—usually the cartridges will nest perfectly against one another. That is, each round is in contact with four neighboring rounds. A magazine that allows for proper nesting of ammo makes the best use of capacity given a certain size. This type of magazine generally features what is known as a dual presentation at the feed section. The ammunition remains in its own vertical column as it rises into location where the bolt may strip and feed in into the chamber. Cartridges are loaded alternately from the left, then right, then left side again. The magazines of the UZI and AR-15 clearly demonstrate this type of feeding. 

Some mags provide a single presentation at the feed section. That is, the two columns of ammo are forced to merge into a single row before being presented into the bolt’s path for stripping and loading into the chamber. The weapon loads ammo from the same central location every time. These mags typically use a staggered but not a perfectly nested storage configuration. The internal width of these mags is slightly less than that of a properly nested dual presentation magazine. As such, they do not make as efficient use of size vs. capacity. The magazines of the Sten SMG and Glock pistol clearly demonstrate this type of feed configuration.

Very High Capacity Drums and Boxes

There have been some exceptional mutations to the basic box or stick magazine. The Finish Suomi KP/31 was a highly developed submachine gun of WWII. It could utilize any of several different magazine types—sticks, drums and something called a “Coffin mag.” The Coffin mag (aka “quad stack”) is essentially two conjoined double-stacked mags. Toward the top, each half tapers and feeds into a single row just before those two single-stacked rows merge into another double row. Then that double-stack tapers and merges again into a single stack up to a single presentation feed section. It’s complex, to be sure. It’s sensitive to the physical condition of the ammunition. It’s sensitive to dirt or sand. And sensitive to any minor damage or deformation to the magazine body. But the Suomi Coffin mag holds 50 rounds, while its length remains equal to the Suomi’s standard 36-round stick mag. This type of magazine has been refined and adapted to the AR-15 platform by Surefire, in a 60- and 100-round option. The AK-47 platform has teased at the existence of a “quad-stacked” mag for some time now, and recently we have seen the commercial availability of such an item.

The proper drum mag may be getting on in years. They have existed for over a century and have been or are currently available for most weapon platforms. There are three types to be encountered. Those with a single row of cartridges tracing the interior of the drum body. This type is common to modern weapons chambered in 12 gauge, 22 long rifle and 9mm Luger. Other drums store ammunition in a spiral—beginning with the single outer row then transitioning into an ever-decreasing circular path. The AK-47, Thompson and PPSH drums are of this type. These always include a cog fan-shaped rotor that carries small clusters of cartridges though the spiral path and keeps them aligned and oriented. The last configuration is merely a double-stack magazine that curves abruptly to the left or right into a circular pattern. Today’s common commercial offerings for the AR-15 and Mini-14 platforms are generally this sort. One exceptional variation to this design is the double drum. The double drum is not new. The German MG15 was fielded almost exclusively with this unique magazine. It presents as a pair of small drums—one to either side of the action. One great advantage of this design is its compact nature. It adds little to no height to the weapon when affixed. It doesn’t impede shooter’s line of sight over the weapon in the case of a top-fed gun, nor does it prevent the shooter from firing from a low prone position in the case of a bottom fed weapon. The double drum was first adapted to the M16 / AR-15 pattern in the late 1980s by the Beta Company. This device became known simply as the “Beta mag.” Unlike the early German incarnation, the Beta mag was designed to be serviceable and adaptable—the feed section could be interchanged to fit other weapon platforms or replaced as required to maintain reliable function. Each half of the mag is indeed a bent double-stack mag, and each merges into a single stack before being introduced to its neighboring single-stack row of ammo to form a new double stack of ammo in a dual presentation feed section. The mags feature a device called a “feed chain” (a common device in many drums mags) that presents as several cartridge analogs joined by chain links. This part of the invention provides constant pressure and feeding while the main follower remains inside the drum body.

Materials and Construction

The first detachable box magazines were made from sheet metal; some were two pieces that were formed and soldered, welded or brazed together. The Sterling SMG magazine was crafted from four strips of steel that were formed then spot-welded together. Later development saw the use of single metal sheets being formed then welded, brazed or soldered along a single seam. The most recent advancements in metal fabrication have provided seamless metal tubing that may be formed into a box magazine. Many early battle rifles featured what we consider today as detachable box magazines; however, these magazines were intended to be kept as part of the firearm and thus often loaded while in the weapon with a stripper clip. These magazines were heavy, robust and expertly crafted from thick steel. The Enfield, Gewehr 43 and FN 49 are examples of battle rifles that were issued with high quality detachable magazines, but each rifle was issued with just a few magazines. The user would replace the mag if and only if required to keep the weapon functioning. The soldiers wielding these rifles were trained and equipped to “top off” an empty box magazine via stripper while the bolt was locked rearward.

The infamous assault rifle of WWII Germany, the STG-44, was among the first high-power assault rifles built without a stripper clip guide. The user would carry a supply of full magazines—as each mag became exhausted it would be discarded and replaced with another full mag. As the magazine became a disposable device, its construction needed to become faster and cheaper. Metal fabrication techniques would have to adapt to fulfil this demand—the disposable magazine would have to be perfect—while retaining the reliability of the hand-crafted reusable magazines of decades past.

Through the 1950s, 60s and even 70s, the magazine was often culpable as a weak point in the battle-rifle equation. Mass-produced magazines were fragile; they were dimensionally inconsistent, and the sheet metal magazine would face compromise, sometimes made from ductile aluminum or made from steel just thicker than foil. Some of these compromises were enacted to satisfy cost restrictions. Some were to satisfy weight restrictions. We can see the struggle of the engineers when faced with government intervention—their attempts to make the best of the mag given certain limitations in cost or weight. One successful way to make the magazine body more rigid was to incorporate grooves and ribs in the magazine body. This technique is still employed by modern manufacturers of metal rifle magazines. Some early sheet metal mags featured bolsters and extra layers of thick plate or even steel castings or machined components mated to the thin sheet metal bodies. The feed lips were a common point of failure, as they are responsible for cartridge presentation and easily damaged by even mild impacts or abuse. The original AK magazine makes a relevant example. The thin sheet metal body would serve only as bulk storage of ammunition while the part of the mag that interfaced with the weapon—the feed lips and locking surfaces—were crafted from heavy castings or even machined from solid steel or aluminum.

The most recent positive change in the development and perfection of the magazine would inarguably be found in polymer science. Synthetic magazines were around as early as the 1960s but not as we know them today. Early magazine endeavors to craft the magazine body from lighter and more resilient materials produced what today we would call composite construction. Back to the AK platform for another relevant example; Russian designers were experimenting with phenolic resins and other synthetic bonding agents melded with organic fibers, or vice versa, synthetic fiber bound in a matrix of organic bonding agents. These early polymer mags were lighter than steel, tougher than aluminum and highly resistant to the failures associated with environmental exposure common to the field of battle. Although at its infancy, the synthetic magazine of the 1960s and 70s would cost more to produce than its comparable sheet metal version. As with all new technologies, time and science would solve this problem.

Today, without much need for a supportive example, it is safe to posit that polymer has been established as king of the hill. Most major arms manufacturers today have succumbed to crafting at least a few magazines from polymer. Even the mighty Heckler and Koch, arguably the best sheet metal crafter in the world, now makes polymer rifle and pistol magazines. With that assumption, many pistol magazines are still made from steel. And even Glock, famed for the plastic gun they brought into popular favor, still furnishes a steel magazine, which has been clad in a layer of polymer. Only by very recent advancements in exotic plastics such as flouropolymers have manufacturers been able to produce consistent and reliable pistol-caliber magazines that can compete with the longevity and performance of the best metal bodies.

Failures

Since WWI, the Japanese produced one exquisitely deficient machine gun—mostly faulted for how its ammunition was fed. It was called the Type 11 and had a hopper mechanism that fed 5-round strippers full of ammo into the gun—the same strippers used by the infantry to feed their bolt rifles. Seems like a sound idea, until one learns that the hopper only held six stripper clips (30 rounds—enough for almost 4 seconds of fire). Keeping the Type 11 full of ammo was a full-time job for one man while another man would aim and fire the gun. 

The Italians managed to impress and fail simultaneously. One of the most beautiful WWII weapons is the Breda 30. Today it is regarded as a treasure of the old world and appreciated as a tragic work of art. When one considers its battlefield prowess, the Breda makes the list for not having any. The magazine was hinged to the gun—not detachable at all. The box would pivot forward to facilitate loading with a 20-round charger before the magazine would be rotated back into position. Every time the charger was inserted into the magazine, dirt and debris was also introduced. Particulate and foreign material would build up in the mag to the point of malfunction. The magazine featured an opening to provide a visual indication of remaining ammo supply and another way for dirt to get into the gun. This arcane beauty can barely be considered a machine gun at all. But the mechanism and magazine are unique enough to deserve an honorable mention.

Notable Variations and Exceptions

The basic pattern of the high capacity magazine has been rubber-stamped across the industry: sheet metal or polymer body; coil spring; and plastic anti-tilt follower. Just apply a few dimensional specifics to this basic recipe, and one can provide a magazine for almost every weapon on the planet. Some designs have deviated from this basic approach. Sometimes a bit of extra complexity can solve a real-world problem. The following are a few examples of some magazine designs that have stepped out of line a bit in order to enhance the form and function of the weapons they feed.

Helical Magazines

These are rare but not totally unique to any one weapon platform. A helical magazine arranges and stores ammunition in a spiral around a cylindrical magazine body. Its advantages are easy to qualify; it makes more efficient use of space than a box mag, and it need not protrude from the weapon like a box mag. Instead, it can lay alongside or under the gun. Ammunition capacity is higher in a helical magazine compared to a similarly sized box mag; ammo can occupy the entire length of the mag as there is no spring and follower under the column of ammo. Instead, a torsion spring resides in the space inside the helix of cartridges. The most notable weapon platforms using this type of high capacity magazine are the US-made Calico and the cold-war era Soviet Bison SMG. Several large aircraft cannon in military service utilize a similar ammunition handling mechanism.

FN P90

The magazine of this PDW (personal defensive weapon) lays atop the gun lengthwise. The 50-round box extends from within an inch of the muzzle back to the shooter’s cheek weld where ammunition is fed into this semi-bullpup “gun” (the P90 is neither rifle, nor pistol, nor carbine). The odd factor here is that the ammunition settles horizontally into the magazine and perpendicular to the barrel. As the ammo descends from the mag into the bolt’s path for loading, each cartridge must rotate 90 degrees clockwise as it drops through the feed “turret” of the magazine. Ahead of the follower there are two free-floating rods—the same diameter as the 5.7×29 cartridge but just too large to exit the feed turret. These rods can perform the trick of rounding the corner and forcing all cartridges from the magazine; a trick the follower alone cannot perform. And the ammunition manages to make this trip at such a rate that this gun can maintain a full-auto rate of 900 rounds per minute. This mechanism is constructed entirely of low-friction polymer materials. 

Boberg Arms XR9 (Currently Bond Arms Bullpup)

This small firm created a compact semi-auto pistol with a very special magazine and feeding process. The unique engineering allows the XR9 (Bullpup) to count itself as the smallest semi-auto pistol in the world per given barrel length. The key piece to this puzzle is how the magazine dispenses ammunition—to the rear. That is, ammunition is extracted from the magazine as the slide travels rearward. As the slide is under recoil, the mag presents a cartridge into a position where a pair of arms can grasp the case rim and pull it from the mag. As the slide starts forward, the round is elevated above and over the magazine and into alignment with the barrel. The advantages of this system are clear: the barrel can be longer than other pistols of similar overall size (chamber is above the mag, not ahead of it). Also, the extraction cycle is performed by direct energy generated by the fired round rather than stored energy from a compressed recoil spring. However labored the operating cycle endured by this little pistol, its magazine will surely remain among the most unique. And to make it sound even more unlikely, the magazine has no follower.

The “Beta” 100-Round Double Drum 

Shown here in the original patent description is the Beta 100-round double drum designed by L. James Sullivan of AR-15 and Ultimax 100 fame; how it places the ammunition supply in a tight efficient location at the sides of the rifle.

This magazine can be fitted to a rifle without interfering with any handling or operation required of the user. The only disadvantage to a 100-round magazine of this sort would be its weight when fully loaded.

The ammo supply is distributed equally to each drum and fed to the rifle via the central feed tower.

The Beta mag full of ammunition. Note that at the bottom section the staggered column of ammunition is merged into a single row, thereafter that single column is rejoined with its neighboring column in the feed tower to form a double-stacked, dual-presentation ammunition supply. 

The Beta mag when empty. Note the feed chains in the feed tower. This collection of linked dummy cartridges allows the followers, which are housed only within the drum bodies, to feed ammunition completely through the feed tower. There are two separate feed chains—one connected to each follower, in each drum.

This article first appeared in Small Arms Review V22N9 (November 2018)

Only in the last 30 years has the weapon accessory mounting solution become standardized. In decades (and century) past, scope mounts and sling attachment points have been created and crafted by individual gun builders. Many larger manufacturers’ proprietary systems have survived and become mainstream. Some odd or antique mounting configurations continue to plague their owners by limiting or even making scope mount options impossible. Assuredly, there will always be a place in this industry for the rare and obscure. As well, there will surely be increased demand and need for continued refinement and standardization among these systems.

THE APPLICATION

The tactics and strategies on today’s battlefield are always evolving, so too must our weapons evolve to remain viable and advantageous. Our weapons must be universal and adaptable. The user of any weapon is always better served by a specialized system. Every combat soldier has a role, and every combat soldier’s weapon must be ideally configured to serve that role.

Modern weapons may be asked to don any number of peripheral accessories—Optics: scopes, red dots, magnifiers, night-vision or thermal ocular; Illuminators and target indicators: those that project light and aiming dots both within and outside our natural visual spectrum; altimeters, GPS units, range finders, clinometers and ballistic computers; bayonets, bipods and slings attachment points; forward pistol grips, hand-stops and barricade stops; less-lethal launchers and direct impact devices; belt-boxes; flare launchers; grenade launchers; short-barreled or AOW shotguns; and sheathed knives, spare magazine holders, ammo caddies and battery storage. The absurd is not off-limits to the well accessorized rifle of today. Bottle openers, cup holders, name tags, repelling gear and even a chainsaw have all found their way onto the handguard of an AR-15.

OPTIC MOUNTS

Weaver

The Weaver, by record and merit, deserves an honorable mention. It is the genesis for our current, most successful and widely adopted mounting system, the Picatinny. It is difficult to identify the Weaver’s exact birthdate; suffice to say that it’s old. One can find photo evidence of its commercial presence around 1950. Weaver’s firm (and continuing) hold on the market stems from the fact that it is a highly affordable scope mount system that is easily adapted to fit almost every commercially available rifle. It’s as near a universal system as was ever created. The simplicity and foresight in the design suggests true genius by the developer. The system is based on a simple aluminum extrusion with the operative profile being that of a truncated or flattened hexagon. The wide flat on the dorsal plane features cross-slots, or longitudinally bifurcated cylindrical voids that mechanically lock the binding screws in place. The lateral features of the weaver are opposing convex 90-degree shoulders set at a 45-degree aspect to the top plane. The interfacing ring-mounts are expected to grab the rail below its widest section on the flats that recede back toward the weapon. The sixth side would be the contact patch with the weapon itself. This surface is varied in height and contour to place the upper five planes in common alignment with neighboring mount bases. The weaver system was created with the ideal plan that only a few dozen mounts could satisfy any mounting requirement across hundreds of gun and optic combinations. And it does this with surprising perfection. Confer and verify with any man born before 1960 who still hunts with a blued-steel rifle stocked in real wood. He likely has a set of 60-year-old weaver mounts on that rifle.

The design of the weaver rail, as it is intended to interface with the ring-mount, provides a stable and positive mechanical lock. The ring-mount might engage the top surface and the lower part of the opposed 90’s on the sides. Or the ring may only grab firmly onto the upper and lower faces of the 90-degree side rails—or a combination of these conditions. In all cases, the ring-mount cannot slip or fall off the rail; but only if the ring’s binding screw remains tight. Of course, ideal conditions never prevail in the real world. As scopes get larger and heavier, rifles get lighter, and cartridges become impossibly powerful, stresses on optic mounts can exceed the strength of the materials used in their construction. So, there are indeed shortcomings and downfalls to the weaver system. Heavy recoil can overcome friction and cause a weaver ring to shift on the mount. The round cross-slot does not provide a true vertical abutment to resist recoil, so any shifting of a weaver ring in its base can result in vertical displacement as the ring climbs out of the slot. Even a slight shift on the base can cause the scope to lose zero. Worst case, this scenario can result in a split ring or deformed clamp that can no longer maintain a positive mechanical purchase on the rail.

The Weaver system can be manufactured without the need for high precision manufacturing processes. This is the true genius behind the design. Except that nowadays, there are enough variations in ring mounts and “weaver-type” or genuine imitation bases that some combinations are totally non-functional. The proliferation and pirating of the weaver system kills the guarantee of any level of mounting strength or even compatibility or consistency of datum surfaces and dimensions and spacing between locking surfaces and cross-slots. And of great import today, as we demand flexibility and modularity in everything, a weaver-type mount and ring combination is unlikely to maintain zero after being removed and subsequently reattached. This is all unacceptable to the discerning shootist of today. Modern Picatinny mounting solutions all seem to guarantee 100% return-to zero satisfaction. So, our connection to and application for the weaver may have seen its day. This might see the kind of break up that begins and ends with, “Weaver … we love you, but …” There is in fact little need for concern, however. Weaver does in fact now offer a line of “tactical” mounts and bases. The bases are made from steel and profiled to meet M1913 Picatinny rail spec. The ring mounts are massive and overbuilt from 7075 aircraft-grade aluminum. These are not your grand-dad’s weaver mounts. Weaver’s tactical line surpasses expectation. They’re made from supreme materials and manufactured to exacting standards.

Armalite

The AR-10 carry handle was first used as a scope mount around 1959 by the Dutch. The internal contour and structure of the carry handle on the Armalite AR-10 and later the AR-15 were seemingly designed with the forethought that they would perform as a base for optics. The contour where the mount meets the optic includes opposing 45-degree shoulders that serve to consistently align the optic as it is drawn into the wedge formed by the interior angles. The system only requires a single mounting fastener—usually a knurled nut or screw. One advantage to this mount’s design is its integration into an existing feature of the rifle—no intermediary mounts or adapters are required. Thus, it is light, strong and repeatable. And this mount pattern was designed to maintain full utility of the fixed iron-sights on the weapon. The downside to this system is that the shooter cannot make a solid cheek weld—the optic is placed so high above the intended line of sight, an add-on cheek riser must be used to elevate the comb to an operative height. But in doing so, the iron sights cannot be used. Weapon utility is compromised in this condition. To maintain full utility, the rifle can be aimed and fired with the head suspended above the stock comb. But accuracy and shooter comfort (and thus his proficiency) during prolonged use are both equally compromised.

After the AR-10 and AR-15 projects had moved on, the great men of Armalite would eventually produce the AR-18. This was an attempt to broaden the company’s reach and market share by offering a more affordable option to the AR-15. This weapon platform included an optic base that was formed in the shape of a triangular dovetailed wedge, tapering toward the rear. The dovetail was engineered and oriented such that the scope, while mounted, could only shoot tighter onto the dovetail under recoil. The mount uses a spring plunger to keep the mount pressed firmly forward onto the dovetail in case of reverse recoil or incidental rearward pressure. And as a failsafe, the optic mount incorporated a swinging lock that would be actuated by the user’s thumb before the dovetail could be disengaged. The system allowed for one-handed attachment or removal of the optic from the firing position. As excellent a design as it is, the exact pattern has only ever been used on the AR-18 and its commercial variant, the AR-180. It is an excellent and ingenious device that deserves another chance at widespread success. It is the opinion and wish of the man writing this that Armalite should bring this mount back to commercial presence immediately.

The basic idea of the wedge-type mount may be attributable or derived from other sources. Years before the AR-18 existed, the BALVAR scope and mount from Bausch and Lomb relied on a spring plunger to keep the scope wedged into an adjustable base. The presence of a spring plunger used to press the mount into a wedge is present in several European optics mounting systems. SIG used something akin on the STG57 rifle. We see more modern generation of SIG rifles still using a similar mounting system—with a spring plunger forcing the scope base onto a triangular dovetail wedge (although quite small in comparison to the Armalite). Some mounts for the SIG system feature a mechanically arrested plunger to provide a more positive lock than spring pressure alone.

Warsaw Pact Rail

The Warsaw Pact Rail is commonly encountered on AK variants and other small arms of Eastern-European or Soviet origin like the PSL, SVD, VSS, etc. (post-1950). This rail base is a horizontal dovetail riveted to the side of the rifle; opposite the ejection port. This configuration lends well to the basic design of the AK—the sheet-metal receiver top cover is not solidly affixed to the receiver (some top covers do exist that incorporate a scope base but tend to lose zero every time the cover is removed). The scope mount clamps and locks onto this rail while a simple pin provides a positive stop against the rearmost face of the rail. This hard stop combined with friction generated by the clamping mechanism is generally sufficient to resist recoil. The mount has been proven to be imminently reliable in strength and tends to “return-to-zero” after removal. There are mounting adapters for the Warsaw Pact Rail that provide Picatinny rails, STANAG rails and even direct ring-mounts. The only demonstrable flaw to this system is its bulk and location. Some mounts of this pattern can increase a rifle’s width by almost an inch. The only imaginable failure would be attributed to the height of the mounting adapter. The optical device may be up to 3 inches away from the base rail. This extra-tall structure can compound the moment load on the mount. Perhaps not a demonstrable concern, but the possibility can give pause to the average “western” shooter who is used to a low-set scope mount right atop of his rifle.

Picatinny

The “Pic rail” is obviously based on the old weaver base, but with a more comprehensive, precise and robust structure. The rail’s profile and relative proportions have been refined to provide a predictable and consistent surface for any nominally crafted accessory designed to interface with the system. The Picatinny is correctly named M1913—the MIL-STD-1913 criteria defining the new mount was adopted and published February 3, 1995, by the DOD. Later, it was adopted into the NATO standards of agreement as STANAG 2324. It is presumed that the development and standardization of the mount were in response to the need identified in the first Gulf War (if not all other recent previous military actions). As warfare evolved away from a daylight-only venture on a directional battlefield, our soldiers needed their rifles to exercise some optical versatility. The battle rifle would have to become capable of operating with iron sights, red-dots, short-range and long-range telescopic sights and even dedicated night and thermal vision scopes—and of switching between them routinely. The Picatinny was the answer, and continues to be the answer, to the multi-role universal weapon system. Beyond universal adaptability, the Picatinny ensures near-perfect return-to-zero for optics after removal.

NAR

The “NATO Accessory Rail” is best explained as a redefined Picatinny rail. The new standard institutes a revision in the overall tolerance and operative datum points in an attempt to improve consistency and strength of the accessories meant to interface with the rail. The older Picatinny defined the four outer faces along the edges as the critical interface. The NAR calls out the relation between the top flat and two lower angles as the critical data points. The new definition ensures that the mounting devices made to this new spec make solid contact on those three datum planes. It has been insisted that this system will eventually allow for power and data transfer between the weapon and the accessories and peripherals. This ideal is expected to lead to the integration of smart systems into the battle rifle. Battlefield communication, navigation, onboard logistics and even a soldier’s vital stats are expected to become centralized in the rifle of the future.

STANAG

This is an acronym for “standardization agreement” among NATO nations. There are thousands of STANAGs in place to ensure that we and our allies are operating by consistent procedures and with compatible equipment. For example, the implementation of STANAG 4172 made 5.56 NATO a standard among NATO nations. The STANAG 4179 standardized the magazine pattern among 5.56 NATO chambered small arms. STANAG 2324 defines the universal adoption of the MIL-STD-1913 rail as the optic mount for small arms. Despite all the specifics and code-speak, there is one mount configuration that has become known simply as the STANAG. You’ll be hard-pressed to define it by more specific terms.

This mount pattern consists of a pair of square pockets at each end of the base. These square recesses interlock with lugs that protrude from the optic—usually these lugs are cast into or machined directly into the body of the optical device. Mounting relies on a pair of large screws to fasten the optic to the mount base. Return-to-zero after removal is nominal at best, but the system proved reliable enough to become the most widely used standardized mount system in Europe before the M1913 Picatinny came into favor. The STANAG mount pattern was a standard kit on numerous commercial and military arms from last century. Variants of the FAL, FN49, MAS, Swiss K31, SIG SG-510 and most HK rifles have been originally made, or can be fitted, with aftermarket STANAG-patterned scope mounts. The STANAG mount held enough market shares, as did the optics designed to interface with it, that one can still easily procure any array of adapters to convert a Picatinny-equipped rifle to accept a STANAG optic or convert a STANAG -based rifle to accept adapters for Picatinny style optics.

ACCESSORY MOUNTS

It seems unlikely that the Picatinny could ever be replaced as the prevailing standard as the optics mount for the small-arm. It has experienced continued success as an accessory mounting platform on the battle rifle; its presence may have spawned the booming accessory market as it is today. But there is a great need by both the consumer and professional markets to accessorize and expand a rifle’s capabilities. The obvious place to affix this burden was the handguard. These handguards were typically aluminum and exhibited four lengths of M1913 Picatinny rail at the top, bottom and sides (hence, quad). From the mid-‘90s every premium and professional grade AR-15 was expected to include a “quad” rail as standard kit. Some RIS (rail interface system) handguards are strong enough to serve as a mounting point for other weapons. There are indeed 12-gauge shotguns and grenade launchers designed to grab directly onto a Picatinny handguard. This solves some of the difficulty of removing the lower half of the handguard to expose the barrel for launcher mounting. This capability also allowed launcher mounting on barrels that might lack the specific provisions for direct launcher attachment. Picatinny rails were soon found on upper receivers, buttstocks, magazine pouches and even the sides of scopes and the tops of scope rings. A shooter could accessorize his rifle to a point of nausea. However, the high-profile, obtrusive shape and inherent weight of the pic left much room for refinement. It was soon realized that it was impossible to utilize the total 39 inches of rail afforded by the average rifle length quad handguard. The average shooter might only utilize 2 to 4 inches of rail, to attach one to three peripheral items.

Around 2009-2011, we saw a growing trend in “quad” handguards. They began losing the bottom and side rails—only the top rail section would remain. The rest of the handguard would present with a regular pattern of tapped holes or pockets arrayed around an otherwise smooth handguard. The user was free to attach small sections of pic rail where he needed them. So, the RIS, as it was originally created in the “quad” pattern would soon need to evolve. Many brands released their own modular handguard system, and some still survive as proprietary offerings with a fair fan base. There are two clear heavyweights in terms of accessory mounting systems. VLTOR Weapon Systems gave us the KeyMod, and shortly after, Magpul Industries presented the world with the M-LOK. After exhaustive R&D and the associated cost, these companies made their new standardized patterns public domain. Any manufacturer of weapon accessories could reproduce the mount and the interfacing accessories.

KeyMod

The VLTOR Weapon Systems KeyMod system was the first new modular mounting pattern to become standardized since the M1913 Picatinny. And for many years, it was the best if not the only option to the “quad” handguard. The design is complex as it demands a level of precision in the manufacture of the handguard and accessory mounts. The “key” as it is described, comes from the shape of the pocket. The widest portion is a 3/8-inch round hole, with a narrow pocket extending from one side. The narrow section is relieved on the back (or inside of the handguard). A contoured “nut” passes through the wide portion, and then becomes mechanically locked behind the shoulders of the narrow section. The accessory mount features a fixed cylindrical lug on the back face that locks into the large cutout behind the nut, thus preventing it from slipping out the way it entered the pocket. If the binding screws remain tight in the nut, the mounting arrangement will stay put. The only limitation one might point out is the thin web of material between each keyhole. In destructive testing, this narrow web is regularly where material failure initiates.

M-LOK

The M-LOK pattern calls for a small T-shaped recess in the handguard—narrow cut facing outward while the head of the “T” is cut on the back, or inside surface. Lateral locking is achieved by a fixed stud set between two T-nuts. The stud and one T-nut essentially match up to each end of a short pocket (each pocket is 1.26 inches long), while the other T-nut straddles the web between the pockets (.315 inch). Each T-nut is engaged by a screw—accessible from the outside of the accessory adapter. Upon tightening the screw, the T-nut swings 90 degrees until the head of the T comes into full mechanical interference with the back side of the slot. The nature of this design transfers load forces to the steel locking screws and appeals directly to the strength of the material used in the handguard’s construction.

These two systems provide the same service—modular accessory mounting on a rifle’s handguard. Some have wondered, and others argued, about which is superior. Pullout and shear strength of the M-LOK have been tested and proven to be superior in strength to the KeyMod—up to three times stronger under abusive testing. Some M-LOK pattern handguards have been tested to resist 1,400 pounds before mount failure. KeyMod can be expected to fail near 400 pounds. Also, M-LOK’s return-to-zero after removal is up to 50% better than KeyMod. That said, most accessory mounting bases are short Picatinny rail sections fastened onto the handguard, and accessories are mounted to those rail sections. It is safe to assume that under actual use, only the accessory would be removed from the Picatinny section; the Picatinny’s return-to-zero is largely dependent on the clamp or mount chosen. It is worth noting here, that direct-connect accessories do exist for each pattern. These accessories are largely limited to flashlight mounts, forward grips and sling attachment points.

And as far as abusive testing to the point of material failure, by all intents and purposes, nobody who has bought a rifle with their own hard-earned cash should ever be expected to subject their rifle to that kind of use. As these patterns are indeed open-source, any company may produce the handguards as well as the accessory mounts for them. The patterns are well defined, but there is no guarantee as to material quality or dimensional tolerances used in their construction. Once again as we see the proliferation of a market we will also see knock-offs and clones and the diminished quality that comes with them. Any of these handguards would be more likely to fail under normal use due to material and manufacturing faults than failure directly attributed to the mounting pattern you’ve chosen. Quality never disappoints. The comparison test in reference above was performed by USSOCOM, and results were published in May 2017. The test is exhaustive and conclusive; it’s worth a quick study. The numbers demonstrate fact, but real-world application and consumer acceptance will decide the fate or coexistence of these two mounting patterns.

There will always be room and opportunity to improve on any current system. It might seem unlikely that we’ll see any major shift from our current systems considering our current state of refinement and the level to which the world has become vested in the Picatinny-type rail. The NAR might just be the last chapter in this treatise.

This may be the first piece of armor that every man can put to good use. We all don’t find ourselves in the path of incoming gunfire or breaching buildings in search of terrorists or hostage-takers, but may indeed find ourselves putting our bodies at imminent risk of damage, or at least discomfort. Motorsports, team sports, or some careers may ask that we take a bump here or there. Imagine the level of protection that comes from a “cup” made of ballistic material- capable of stopping a bullet. Yes, NUTSHELLZ makes a bulletproof cup. They were initially developed for the armed professional (police, SWAT), but have also found favor with athletes and soldiers. The NUTSHELLZ cup is more pliable and ergonomic than the typical unit found in a sporting goods store. This cup features a ventilated rubber rim. An added benefit to donning the NUTSHELLZ is the tremendous confidence that comes from knowing that your important bits have never been safer. This elevated confidence level has been shown to improve performance on the job and on the field by reducing an individual’s inhibition and restraint in a physically demanding scenario. NUTSHELLZ are available in level 1 (Kevlar) and level 2 (Spectra) ballistic protection. Injuries to the genital region of the body and complications thereof can be very severe, and the ill effects of injury can be life-long. NUTSHELLZ offers the best protection. And yes, live-fire demonstrations have been conducted on human test subjects. SAR does not recommend live fire testing of this product.

NUTSHELLZ. www.armorednutshellz.com

One must not underestimate the importance of practice when it comes to the carry and potential use of a firearm. Simply having a gun does not fix all your problems. If and when your sidearm is called on to protect against someone intent on doing you harm, that sidearm must be an effective and instinctive tool in the hand.

Umarex aims to make you better and more effective with your pistol of choice. In fact, Umarex currently offers almost 60 “stunt doubles” to match your current handgun lineup. There are BB and pellet variants. There are blowback and non-blowback variants to many of the offerings. SAR really does suggest browsing the Umarex website to see the available product line. It’s impressive. It’s comprehensive. The idea is that you can buy a very inexpensive (from about $50 on up to $250) clone of your favorite sidearm, that shoots BBs. Yes, we speak of air guns. They’re not just for kids anymore. These are detailed operational replicas of full-power centerfire and rimfire pistols. These BB guns can be utilized for target practice and handling familiarization and drill practice without the expense and restriction of shooting a firearm. No trip to the range is necessary. These can be put to use in the basement or garage, provided an appropriate “trap” to collect the BBs. Sure eye protection is still recommended, but imagine the advantages and sense of security that comes from becoming really handy with your carry piece.

SAR was provided with the Umarex analog to the Walther PPS. The PPS is a player in the budding field of slim carry pistols. It’s less than 1” in width, as all the controls are blended into the outside contours of the pistol. There are no snags and no protrusions. It’s a proper compact pistol that makes for excellent concealability. The slide and frame contour is totally melted down to remove every corner. The grip does manage to maintain a full hand placement (no loose pinkie) while offering a minimal print signature under clothing. It’s a fantastic carry piece. The Umarex CO2 powered clone matches the Walther PPS on all counts. The only shortcoming was a 2 ounce disparity to the total weight. That’s easy enough to overlook. The Umarex with a fresh CO2 bottle is only peanuts off the weight of the PPS with an empty mag. This minor detail is easily forgotten.

The operation of the Umarex PPS is very close to the real thing. The 18 round magazine loads from the bottom of the grip. The slide reciprocates and delivers a satisfying kick when fired. The slide release is totally functional as in the real firearm. The trigger pull is smooth and accuracy was actually better that with our own 9mm PPS. Steel 3-dot sights and a functional accessory rail for flashlight use make this a dead-ringer for the real thing. Even the modular grip panels are present- only in the CO2 gun, the grip insert conceals an integral hex key for activating a CO2 bottle. And for added realism we actually experienced two “jams” during a 500 BB play date with the Umarex. The slide became stuck rearward and forced user intervention to correct the failure to get the gun back into play. Good for Umarex. We prefer and expect that this practice analog deliver a realistic experience to validate it as a trainer. There could not be a better way to practice and become proficient with a pistol.

Umarex USA. 7700 Chad Colley Blvd. Fort Smith, AR 72916. https://www.umarexusa.com

Truvelo Manufacturing began in the 1960s in South Africa, manufacturing electronic devices. In 1994, the Truvelo Armoury branch was formed and entered into the manufacture of high-quality rifle barrels and bolt-action receivers. Their market share included both civilians and military and government agencies. As their processes and capabilities continued to improve and expand they unveiled a complete line of professional grade precision rifles. The selection of precision long-range rifles from Truvelo demonstrates supreme quality and performance. Truvelo has garnered our full attention by implementing robust design and a rare measure of practical thinking in the creation of their rifles… which are now available for sale in the United States.

The Truvelo Counter-Measure Sniper rifles (CMS) meet the demands of the professional marksman in the roles of anti-personnel and anti-materiel interdiction. These rifles are available in 6 calibers (though some are restricted); .308 (7.62 NATO), 338 Lapua Magnum, 50 BMG (12.7×99), 14.5×114 soviet, 20x82mm, and 20x110mm. Assuredly, almost any stationary target at an identifiable distance can be successfully engaged with one of these weapons. The 7.62 can be used to good effect on soft targets and unarmored combatants out to 800 yards. At the extreme, the 20×110 fires a 2000 grain projectile at 2800 fps and generates 35,000 ft/lb of energy on target. This rifle can be expected to hit and penetrate… and maybe destroy hardened and armored targets at 2500 yards. The 20mm projectile is large enough to carry a significant payload, which can offer “enhanced effect” on target- to include high-explosive, armor-piercing incendiary, and the indiscriminate crowd-pleaser, the SAPHEI (semi armor-piercing high explosive incendiary).

The rifles displayed herein represent the 3 smallest offerings- the 7.62, .338, and .50 BMG which are available on the retail market. We assume these will be the most commonly demanded, thus most commonly encountered by the armed professional and well-informed sportsman. At first encounter, the Truvelo rifles are intimidating. They’re heavy and thick. The lines and contours are abrupt and totally utilitarian. But at close inspection and in operation, we found these rifles to be refined- care and attention were given to the details. The machining and final finish on all metal parts is perfect and smooth. The fit of all components is tight and seamless. There’s no rattle or wobble in these rifles. The bolt opens with a solid, audible crack- then glides through the receiver smoothly. The bolt does not ride in broach-cut races, as most bolt actions do- it runs through a perfectly smooth cylindrical bore cut through the receiver. The round bolt body is fully supported around its circumference so it cannot bind or tilt during operation. The bolt is helically fluted- this extra machine operation lets the bolt make less contact with the receiver bore, for reduced friction, while providing an escape path for debris and particulate matter that may settle in the receiver. The bolt’s lugs are cut into the diameter of the bolt body (rather than protruding from it). This configuration allows for the simple cylindrical receiver bore. There are 4 locking lugs- so the bolt handle only requires a 40 degree rotation for operation. It’s strong, positive and fast. The extractor and ejector are larger than they need to be- in support of the design ideas behind these over-built rifles.

The receiver-mounted Picatinny scope rails are machined from steel and include a third degree forward tilt (20 MOA) for long range zeroing capabilities. Also being over-engineered, the scope mount rails are held on by 6mm socket screws (equivalent to SAE 1/4×28). This mounting should allow the scope to endure triple the shear forces that more “domestic” rifles could never expect to survive. In both design and dimension, the scope mount is overbuilt. It’s much longer than most commercially available mounting options. This extra real-estate makes it versatile and adaptable. The extra mass makes it strong and reliable. It’s also worth noting, that a few years ago there had been some change to the standard Picatinny rail interface- the critical dimensional criteria and tolerances were revised- to allow better clamping consistency and capability, while ensuring reverse compatibility with any accessory designed to the old dimensional standard. This new rail interface has been labeled the NAR, or NATO Accessory Rail. What’s important here is that the Truvelo CMS rifles feature scope rails that fit this new standard.

The trigger mechanism is what we would expect on a professional-grade rifle such as this. The trigger pull offers good feel and feedback- without being overly sensitive. The pull weight approaches 4 pounds and the take-up is longer than most “match grade rifles” would exhibit. At the same time the trigger is not handicapped by any sort of roughness or inconsistency. This kind of trigger pull expects the operator to be committed and in tune to his task and deliberate in his choice of action. It’s the right piece of hardware on rifles such as these. It’s fully adjustable, should the user find any room for improvement. The safety lever is located just ahead of the trigger blade inside the trigger guard. The way it’s situated makes it almost impossible to forget to deactivate the safety before taking a shot. The thoughtful design of the safety basically lets the operator keep the gun on safe, until his finger approaches the trigger to fire. By doing so, the safety is automatically bumped into the “fire” position by the trigger finger. It’s a very positive safety with fast passive control. The control lever for the detachable magazine is integrated into the profile of the trigger guard- so the “shooting” hand can drop the mag while the free hand is retrieving or replacing the magazine. The magazine release lever does take considerable effort to operate. This protects against accidental mag drop during handling.

The stock of the CMS is not totally unique- it’s just good technology- and probably derived as a common conclusion by most designers and users of precision rifles. It consists of an alloy substructure that houses and connects the barreled action, trigger-guard and detachable magazine box, furniture panels, and folding mechanism for the stock. The substructure protrudes from the front end of the plastic enclosure to present a 3 rail accessory boom and a spigot for a quick-detach swiveling Gibbs bipod. The grip seems to be borrowed from the AK pattern rifle. The folding and adjustable stock is standard to all Truvelo CMS rifles. The locking hinge mechanism is very solid- as stated before, there’s no wobble anywhere. The button is easy to actuate to unlock from the open position. And as long as the bolt handle is lifted, the stock will lock into its forward folded position. The requirement to lift the bolt handle ensures that a loaded rifle is not placed in storage or transport. The action of deploying the stock from the stowed position is not as quick- the user must lift up on the butt assembly then swing it out and back- this action takes a bit more strength than folding. The cheek rest is not infinitely adjustable- it can be locked into a number of mechanical notches- spaced about ¼” apart. Though the user may not be able to access just that perfect height, this arrangement is very solid- and cannot slip out of location. That is a welcome compromise. The buttpad is adjustable vertically by means of a rotating locking lever. It can be adjusted (with the free hand, in firing position) approximately 1” up and 1” down from its central location. This aspect does indeed allow a user to match the rifle to his unique body geometry- the proportion of the head, neck, and shoulder. The stock features an accessory rail at the ventral edge for affixing a rear monopod.

Truvelo Armoury cut its teeth making rifle barrels- from .22 up to 40mm. They are a premier OEM supplier to many other arms manufacturers worldwide. And of course, the CMS rifles all come outfitted with the best Truvelo can muster. Their own rifles however, get an extra dose of “special.” All CMS barrels are fluted- heavily. The 8 groove pattern is aggressive in pursuit of material removal. And that’s what is required to make fluting worthwhile. Most gun manufacturers put fluting there for looks while Truvelo gets after it and makes the grooves deeper than they are wide. Now let’s kill the misconception- fluting does not make a barrel stiffer (than unfluted of the same size). The process of removing longitudinal sections of barrel steel is used as a means to affect some weight savings while maintaining most of the original rigidity. So comparatively, a fluted barrel is stiffer than a non-fluted barrel of the same weight and length. And a fluted barrel is lighter than a non-fluted barrel of the same length and diameter (but not more rigid). That said- these rifles are not lightweight by any means. Truvelo barrel contours exceed what American brands might call a bull barrel. The “root” of the barrel- the section that meets the receiver is about 25% larger than some mainstream American brands. So even with the weight loss from the deep fluting, these barrels are still heavier- and thus stiffer than any mass produced big brand rifle on the shelf today. Adding a lot of extra metal is the wise caveman’s approach to making an accurate rifle.

The 7.62 is the only CMS that is not born with a muzzle brake. The muzzle is threaded to accept a suppressor. The 7.62 has moderate recoil, and lends itself well to dedicated suppressed use with full-power or short range subsonic ammunition. The muzzle brakes on the .338 and .50 are good designs that boast 60% reduction in felt recoil. Without access to an appropriate laboratory and equipment to prove that claim, we were content to just shoot the rifles. All we can confirm is that the muzzle brakes are more than adequate; the recoil forces produced by these rifles are very manageable. The .338 produced no more felt impulse than the 7.62 rifle. The recoil from the .50 was like that generated by a 12-gauge firing a full-power 3.5” magnum shell. Stout recoil, yes. But very controllable and not totally unbearable. Considering that this is a fixed breech rifle, recoil force is always going to be higher than a semi-automatic.

The included Gibbs bipod is of the famed Parker-Hale design. These bipods may look old fashioned to some, but don’t be fooled by popular consensus. The Parker-Hale design allows for the user to freely swivel and tilt and pan his rifle (within a narrow field) without being tasked with loosening and tightening locking levers and knobs. The free motion of the Gibbs pod allows a shooter to easily match and track the motion of a moving target or pan and scan a target area. Once presented with a target and firing solution, the sniper need only apply forward pressure to the rifle; this will cause the joints of the bipod to bind up and become quite solid. The legs of the Gibbs bipod are extendable and may be folded forward or backward when stowed. The Gibbs pod only showed weakness while supporting the .50. The rifle, being so heavy, took constant attention to keep it under control. A rifle of this bulk and weight may need a more rigid bipod configuration. But the .308 and .338 could be adequately controlled and stabilized with the rear support hand.

We tried firing the CMS 7.62 and .338 off-hand but found it difficult to maintain good control and balance. We could not utilize the ideal forward hand position- the Picatinny accessory boom occupies that space. With the exception of the 7.62 version, these rifles are too heavy to fire free-handed anyway. These rifles definitely favor a rested firing position. So again, that’s a compromise we can accept. Truvelo did allude that there may be forearm options in the works- possibly extra panels that can be attached over the Picatinny accessory boom to form a more conventional profile.

Putting the Truvelo rifles to work was a special opportunity. As staff of Small Arms Review, we get to field test many types of weaponry. The Truvelos stood out among other precision rifles we’ve spent time with. The heft and quality feel of these rifles seems to instill the operator with an added boost of confidence. We would employ premium ammunition to demonstrate the accuracy potential of these weapons. The .308 fired Black Hills Match with a 168 grain Match King. The .338 was also fired with Black Hills Match ammo- with the 300 grain Match King bullet. Hornady Match with a 750 grain A-Max pill was fed to the .50 caliber. We used our best judgment (referring to the twist rate of the barrels) for bullet weight selection, and relied on the reputation for quality from these 2 ammo manufacturers. All three rifles were fitted with the Nightforce BEAST scope for testing. Considering that the scope is the only connection the rifle and target share- a rifle’s potential for excellence can only be viewed through perfect glass. The Nightforce is unmatched and would allow us to exploit the Truvelo’s talent. The Beast goes way above and beyond. We found its clarity and resolution to exceed our Kowa spotting scope. The reticle’s subtensions and click corrections are absolutely accurate.

We had assumed that at this level of expected quality, the Truvelo would “just shoot” and not exhibit a tendency to favor a certain ammunition type (which is usually the case among small arms manufacturers). Our range day would take us into the vast open of the southern Utah desert on the day after a storm. The sky was still overcast, so no mirage to deal with and the wind had blown itself out- we had perfect conditions. Given such a perfect day, the “Truvelo Trio” performed famously. All returned sub MOA accuracy on a paper target at 300 yards. We engaged a hanging 12”x18” steel plate at 600 yards; all three rifles found this test too easy. At 850 yards the .308 gave up 30% of its hits to waning bullet stability. With the .338 and .50 we were able to continue to ring the 12×18” at 1200 yards. The .50 begged for more, so we took her to task on that same steel at 1600 yards. At this distance- just shy of a mile- a successful shot indeed owes much to the shooter. But indeed, the shooter owes as much to his rifle and scope. Without embellishment, we connected with that 12”x18” plate at 1600 yards on the fourth attempt. At that range the sound of the impact could not be heard- but the energy of the 750 A-Max made visible effect on target.

It is becoming obvious that there are too many “sniper” rifles made for the masses that just miss the mark when it comes to the why and the how of the engineering and final execution. The market has become diluted with hobby-level hardware and mediocre quality – all displayed as the next tactical fashion trend or promoted as the new “game-changer.” Considering the plethora of long-range precision rifles we’ve been able to review, Truvelo rifles will be counted among the best. Truvelo gives us hope- they have not lost sight of real purpose for their craft. Truvelo rifles demonstrate perfectly simple rock solid utilitarian design in long-range weapon that can support the demands and exploit the abilities of even the best shooter.

In the United States, Truvelo 7.62 x 51mm, .338 Lapua Magnum, and .50 Cal BMG rifles are available from Gun Mountain LLC, 410 Marks St, Henderson, NV 89014 Tel: 702-564-3272 website: www.gunmountain.com

When you pick up one of your firearms, or peer at a new one though a glass pane… likely that all you’ll ever feel and see is the outer surface. This outermost finish must be visually pleasing to the eye and supremely protective to wear, age and abuse. The science and engineering of the materials and internal mechanisms of a firearm could be considered remedial when compared to the high science behind surface coatings and treatments.

To simplify, one could divide this discussion into three classes. Coating will embody any layer or film that may be directly applied–like paint. Plating will encompass the deposition of material by electrical, chemical, or other passive means. And conversion–where the substrate material is altered or manipulated on a molecular level to produce desired properties. All of these treatments and finishes serve the same purpose; to protect and enhance a firearm’s performance and appeal. But there is no clear winner among these categories as to durability, economy, or performance.

Coatings

The current crop of high-performance paint (essentially, that’s indeed what they are) comes by many names, though not all created equal. This class of paint includes the likes of CeraKote, DuraCoat and Gun-Kote (to name a few). These are usually 2-part epoxies that must be baked on. There are “air-cure” options available as well, although these are demonstrably less durable. These coatings may be applied to steel, aluminum, plastic, and wood. They require no more special equipment than a paint gun and an oven for baking if that is required. They do however ask for fastidious and nuanced preparation and execution. Should the finish fail or become unsatisfactory due to use, abuse, or wear, these coatings are quite easy to repair– just prep and re-apply. One distinct negative side-effect of all coatings of this type– they are quite thick– that is, they “build” the surface considerably when compared to metal plating and surface conversion. This can be good– take for instance, a poor-fitting war-era 1911 pistol. It may rattle and present with disappointing accuracy. CeraKote can be counted on to fill in some lost tolerance between working components. Use of these products, for this purpose is becoming common practice. When using a high-build coating prior to application, it is imperative that tight-fitting “working” surfaces are masked and protected from the impending encounters with a sand blaster and paint spray-gun. Best case fix after poor preparation, excess paint or overspray may need to be scraped off to allow reassembly. A worst case possibility– from gross negligence–if left in the corners and crevices, residual blasting media can become permanently cemented to the gun by the paint film. This condition has been observed to be the cause for undue wear and possible failure of a firearm. The lesson to be learned here and now is that CeraKote, DuraCoat and Gun-Kote should always and only be applied by an educated, certified and authorized purveyor of that service. Beware the new local startup advertising gun refinishing service.

These spray-on coatings are becoming more than just a color option– some make sound, practical argument to their own favor. Among the three brands listed here, there is one that makes a coating that claims to subdue infra-red signature. Others boast operability in extreme environments– attributed to some genius stroke of science on the microscopic scale– by including Teflon, graphite, and similar polymeric compounds suspended in the paint film to reduce friction and thus may require no liquid or other chemical lubrication. All said, and aside from any practical purposes, these coatings have brought about the age of tactical fashion–an arms “image” race. There is no color combination or derivative thematic appeal that cannot be captured by the artistic application of the aforementioned high-performance paint.

There is a long-standing presence of more specialized “in-house” coatings. These were around long before the “take and bake” bottles of gun paint ever hit the market. They bear industry labels like Ro-Guard, Black Ice, and Black T (to name a few). These represent a less pedestrian class of “paint.” They are applied in very controlled conditions and with very special equipment. Some are described as a “matrix” of metal, polymer, or other solid lubricant. This type of coating is not available in a bottle to the end-user; even one with the most distinguished DIY credentials. No–these are proprietary and protected processes. One must ship a firearm to these companies to receive the special treatment. These types of coatings are typically well proven and have been tested and vetted by industry experts and armed professionals. These treatments come with certifications and guarantees and documented performance records. They promise perfect consistency and ultimate protection and performance. These are to be regarded as a step above– not mere paint. Some of the heavy-hitters in the gun business reserve some “secret-sauce” high-performance coatings for their own use only. For example, Beretta faithfully employs their home-grown “Bruniton” finish. And Heckler and Koch is extremely proud of their miracle “Maritime Coating.” These are typically black– no color options–all business.

Plating

Plating is basically just a very thin layer of metal– less than a thousandth of an inch– bonded to a metal surface sub-structure. The two types of plating most abundant in the gun market and worth a mention are Nickel and Chrome. These metals are applied either by electroplating or acid deposition. In years past, Electroplate was the most common, as it was cheap and easy to execute en masse. However, electroplating is prone to some inherent problems. The uniformity of the plate can be difficult to maintain. So much variation can occur that at one extreme, a gun cannot be reassembled– on the other extreme whole areas of metal may be missed by the plating process. Also, any deformity or pitting in the substrate metal can turn into voids or pinholes in the plating. These micro imperfections leave the plated object unprotected– and susceptible to oxidation and ultimate failure of the finish. Also, electroplate finishes can be less elastic than the substrate material. So as dents and scratches occur, the plating can detach from the surface and the failed bond can propagate across the entire surface. This type of failure is evident on many older nickel plated handguns. Very few of those pistols and revolvers have kept their original nickel finishes over the last century. Electroless deposition has been found to be superior for all applications. Film thickness can be precisely controlled. Electroless plating ensures a smoother finish on the micro-scale– thus a more lubricious surface. It provides a harder finish as well. This process can be used to apply nickel or chrome directly to steel and aluminum, where electro-plating may require various layers of more compatible metals before receiving the final finish. Electroless nickel has become a standard option among Europe’s big brands for a non-black gun. Nickel presents with a subtle rose or bronze tint, while hard chrome always exhibits a pure silver color.

Electroless nickel and chrome have been tested to be more corrosion resistant than stainless steel– and they won’t wear or gall like stainless can. Due to the ultra-smooth micro finish high-wear or high-temp parts protected by electroless plating are far less dependent on chemical lubrication to maintain smooth operation. The acid deposition process is also compatible with low-friction polymers. Nickel and Teflon have been brought together in a composite matrix to create a very formidable surface treatment. The coating is called NP3 and the company offering it is called Robar. NP3 boasts all the advantages of the individual components– high resistance to wear, chemical attack, zero friction; and a diminished need for lubrication, etc… without any of the inherent weaknesses of those constituent components.

As good as it is, even Nickel-Teflon can be one-upped– by Nickel-Boron. It is applied in an alkaline solution instead of an acid. However it’s created, it is incredible stuff. It’s been tortured and proven in all manner of testing. Many manufacturers now offer Nickel-Boron as standard kit on their gun parts. It is becoming the standard go-to metal treatment where high load, high heat and regular abuse must be endured. It can be applied to any metal from aluminum to the hardest of tool steels. The most common use is on AR-15 bolt carrier groups. Increasingly, small parts– triggers and such are being plated in Nickel-boron. One company, Patriot Ordnance Factory, is plating their entire upper and lower receivers in this nickel-boron matrix.

The most exotic, supreme metal-plating technologies are known as PVD– physical vapor deposition, CVD– chemical vapor deposition, and TRD- thermo-reactive diffusion. These processes can impart super abilities and attributes to a metal object. The “vapor deposition” process requires that the object to be plated be positioned in a special vacuum chamber – often referred to as reactor. You read that right- a reactor. The object to be plated is heated by induction, radiation, or direct electrical current. The material to be used as plating is introduced into this chamber as a metal vapor or gas- achieved either by chemical dissolution or laser vaporization. To clarify, an ingot of sacrificial material is either dissolved in acid or it is “blasted” from a stable solid state by a laser to create a cloud of free reactive molecules- which will find their way to, and bond with the target parts in the reactor. To be general, the compounds in PVD, CVD and TRD finishes form oxides, nitrides or carbides of metals like titanium, aluminum, zirconium, iron, and vanadium. PVD, CVD and the like can be applied without any measurable change in dimension to the original part. The micro-structure of these finishes is perfectly smooth. The breadth of features and attributes and superiority of these sorts of plating are beyond contention. These coatings make possible the modern age of manufacture- in fact the machine tools used to make guns today are treated with these coatings. Wear, abrasion, friction, and the resultant failure they cause are non-existent. Many companies offering these surface platings insist that parts never require lubrication. This is true-the substrate metal will tend to fail from fatigue or fracture before CVD or PVD plating gives up (but you should still lubricate your firearms). Many small gun parts- triggers, bolts, muzzle devices and the like are now offered with these supreme finishes. One company in particular has capitalized on new plating technology- Cryptic Coatings. They make the smoothest, longest wearing (and prettiest) AR-15 bolt groups available.

There is an extension of the technology derived from PVD and CVD processes- which deposits an atom-thick layer of carbon- that approaches the structure, and thus, the properties of Diamond. This is called DLC, or “Diamond-like Carbon.” Such a hard finish with such a micro-smooth surface is beyond good stuff- perhaps too good for most gun manufacturers. The price and prevalence of the technology would suggest this. Though still very uncommon, DLC is slowly finding its way to into our favorite guns.

Surface Conversion

The last type of treatment to discuss can safely be called surface conversion. These types of treatments differ from coating and plating in that the substrate metal is directly involved in the formation of the protective film. Substrate metal is neither removed nor covered up. New material may be introduced and bonded with the surface of the metal substrate, but the substrate material lends itself to the final result. It becomes part of the “converted” finish. These surface conversions can be achieved during a heat treat or quench process, as found in the increasingly popular “nitride” or “nitro-carburized” processes. This sort of treatment finds its roots in the old fashioned color case hardening of steel. That old “casing” process produced a carburized skin on steel’s surface. Now with better controls and technologies, the process has been manipulated to provide even greater effect. Steel, aluminum and titanium become totally inert and very hard- even as hard as glass- by the introduction and diffusion of nitrogen (nitride) into the surface. Nitride and nitro-carburizing processes have come to be known by many trademarked names, but for all intents and purposes, they are similar enough to save further conjecture. They’re close enough to the same as it doesn’t matter.

Bluing and Parkerizing are the oldest standardized surface conversions intended to protect the surface of steel parts. Bluing is formed by oxidizing steel under controlled conditions to form black oxide, rather than rust, which is the result of spontaneous oxidation. Bluing is usually encountered as a smooth and shiny black or blue/black surface, but can be achieved in a matte finish by media blasting or etching the substrate steel first. Parkerizing is created when steel is exposed to phosphoric acid solute with zinc or manganese. Parkerizing can be a more durable alternative to traditional bluing; the reason Parkerizing has been the choice of our armed professionals for the past 75 years. Both processes are antique science, but still receive due attention from manufacturers. Bluing is beautiful. Parkerizing is nostalgic.

Aluminum is all too common these days, for it is the stuff that makes the AR-15. Aluminum’s surface can be painted, plated, and converted by all sorts of new methods. But the oldest way to treat aluminum may still be the best for broad application- anodizing. In its raw state, aluminum alloy will oxidize very quickly. This thin oxide layer cannot be seen, but it can be measured- it is very abrasive and exhibits high friction. So to be of any use in a mechanism, aluminum’s skin must be treated to become inert in a controlled and predictable manner. Anodizing comes in several different styles- each described by its “type” of which there are 3. Type I is regarded as a cosmetic treatment and minimally protects the surface from further oxidation and abrasion. But as of late, the chemicals used for type I have come under some scrutiny by the EPA. It is becoming more unlikely that we will encounter it on the surface of a modern gun. Type II is actually the stuff one will find in a gun shop today (contrary to what many sales pitches would insist). Type II fulfills all criteria set forth per the “mil-spec” requirements addressing anodized aluminum parts. It provides for sufficient surface hardness, reduced friction, and protects from wear and age. It is both cost effective and practical in application. Type III, or “hard-coat” anodizing penetrates deeper and builds thicker on the surface to form a thick “case” of extra hard aluminum oxide. Type III will both build on and penetrate into the surface and results in an affected case-layer up to .004” of an inch thick. Type III anodizing can actually strengthen an aluminum part and lends itself to the strongest alloys and hardest worked components made thereof. Types I and II can be expected to add less than .001” in dimension to the underlying part. Anodizing also (the most obvious reason) allows for a multitude of color to be applied to aluminum parts.

So it is with the surface of most things gun. Is surface coating the final frontier of small arms development? Hopefully not. Assuredly… no. But it’s the new colors and finishes that are easiest to spot. It’s the stuff that catches our eye and sets new kit apart from the old. Judge a gun by its cover? Absolutely.

The Metallurgy of a Blade

This is a discussion for the ages… which steel makes the best knife?

If only there were one simple answer. It all depends on the burden of intended use, actual use, the frequency of use, and potential abuse one puts on a knife. As a basis for the argument, one must first identify the primary use of a knife. Then consider cost. Then maybe, future investment value as many high-end and custom blades appreciate better than most publicly traded stocks and commodities.

Let’s divide the field down the middle- a knife will either be used in a professional capacity or as casual every day carry, (EDC). The professional knife will be taken to task in the course of one’s job or duty. Or maybe remove a seatbelt from a victim of a motor vehicle accident. The professional knife may even see real violence if deployed in close hand-to-hand combat. The professional knife may very well be counted on to protect life, limb and freedom. Or maybe just to skin and dress wild game. The EDC knife, for casual daily carry, may be used to cut packaging or portion food, or may only ever be used as a letter opener. Though, at times the EDC pocket knife could be deployed to protect life and limb from an evil-doer. So the EDC knife may actually get to save the day.

The demands on one knife will never quite be the same as another. We can certainly make sound suppositions about what’s best. Modern technology has lent itself well to the advance of metallurgy to expand steel’s range of abilities. As diverse as modern steel selection is, they’re all very, very good materials. No steel of reputable pedigree should totally and completely disappoint. So even with the wide range of choice, most of our knife steels today will in fact perform satisfactorily, most of the time. Only when pushed to extreme limits will steel ever expose its shortcomings or strengths.

The steels listed and compared here all fall into the categories of Stainless, Carbon, or Tool steel. Stainless steel contains at least 13% chromium in the alloy content, and thus resists corrosion, but may sacrifice toughness at the lower end of the price scale. Tool steel can be very hard and offers the best in edge retention, but may sacrifice corrosion resistance and is more difficult (thus expensive) to craft. Carbon steel is tough, resilient, and easy to work with, but may totally give up on corrosion resistance.

Steel’s performance characteristics can be clearly defined, categorized and compared. Here on these pages are some terrific graphs from www.bestpocketknifetoday.com that display these characteristics in an orderly fashion. We thank Matt Davidson for his contribution to this issue and encourage our readers to visit his website. Edge retention, corrosion resistance, and material hardness are the most important factors in blade steel selection. First and foremost, a knife must cut. According to most serious enthusiasts, corrosion resistance can take a back seat to cutting power. Hardness, toughness, and edge make up the trifecta of a blade’s utility. A blade made from very hard steel is more expensive as it is more difficult to craft, and will be difficult to sharpen. In the case of economically priced blades, one that is easy to sharpen will be equally easy to dull; the compromise can go either way- cheap steel can be too soft or too hard. Either way, the edge will fail. Hard tool steel is more expensive but can be crafted into a thinner edge- which improves cutting power and eases re-sharpening. Only quality steel balances the properties of toughness and hardness to simultaneously resist fracture and deformation. Of course there are trade-offs and there are pay-offs to both economy and premium quality. But aye, there-in lies the rub. One must select a point of compromise. Even the most premium knife steels are not perfect. They always seem to give up a little to gain a little. To complicate matters, new materials are always being created to fill in small performance gaps.

As a guide to material selection, please allow us to make some rudimentary suggestions. Buy stainless or high grade tool steel for a pocket carry knife. Pocket carry knives will endure prolonged exposed to sweat and moisture. They need to be very corrosion resistant. Buy tool or carbon steel for a fighting knife. A weapon of this type may come to bear against an armed and determined foe. It needs to be imminently strong and sharp. Buy carbon or stainless steel for a hunting knife- just keep your carbon steel and tool steel blades clean and dry. If oxidation and corrosion can be kept at bay, you’ll appreciate the performance advantages carbon and tool steels afford over stainless. If attention cannot be given to blade maintenance, pick stainless. And if you choose stainless, carry sharpening equipment.

Another qualifying criteria- one that’s impossible to quantify in a graph would be value for cost. This is largely dependent on the brand of a knife, the steel of the blade, the sort of exotic materials included, and in the case of a handmade custom, the rarity or exclusivity attributed by the artist. Some brands sell quality. Some sell value. Some brands offer rare works of art that appreciate in value and mystique. Some brands sell pure hype and the promise that you will garner envy from your knife-collecting friends.. When studying the graphs, note that some steels may excel in one criterion, but lack in the other two (like 420 SS). These steels tend to be more economical, or suited to one application (420 makes a perfect fillet knife). Other steels that happen to hold their relative position in all three graphs (even if they’re in the middle), can be counted on to be great value for money (VG10, S30V, ATS34, 154CM). The rare few that hold their places at the high-end of hardness and edge retention (S90V, ZDP189, M390) can be expected to appear in pocket knives costing upwards of $400. At the very high end, many knife collectors will give up some corrosion resistance to get supreme cutting performance. One can care for a knife to prevent rust- but by will alone; one cannot make a blade tougher or last longer. It is demonstrably truer in knives than in most retail sectors; indeed, you stand a good chance of getting what you paid for. So it is with steel selection.

We thank Matt Davidson for his contribution to this issue and encourage our readers to visit his website: www.bestpocketknifetoday.com

By David Lake

Polymers and Composites

Drastic changes to tradition can be a hard sell- especially when that tradition finds deep roots in history and culture. If you’re reading this, then you are part of a very special culture- you’re a “gun guy”. And if you’re over 40, then you’ll recall the arrival of plastic pistols. You’ll recall the myths purveyed by the media and the doctrinal arguments hosted by the experts who either celebrate or condemn the idea of using plastic in the construction of a firearm. Despite early skepticism and trepidation, the merit of the concept has been well demonstrated, as now almost every small arms manufacturer offers a plastic gun. Hold-outs and traditionalists are hard-pressed to disprove the advantages in cost, weight, and resilience afforded by plastic.

Accurate terminology is important to this subject. When speaking of steel or aluminum, the generic names can be acceptably applied. Steel… is as strong as steel. And that’s enough. Or close enough as it makes little difference in idle conversation. Aluminum is understood to be very respectable stuff. Structures made of aluminum spend a lot of time performing extreme duties in exotic environments. However, when speaking of plastics and polymers and composites, one must use more specific designations, as all plastics are not created equal. In fact, the word “plastic” should be avoided, as it is not a correct descriptor designation of a type of material; it only refers to a distinct property of material. “Plastic” is not an adequate label for the superlative high-tech engineered materials used to replace steel and aluminum componentry in the firearms of today.

We should at least become familiar with the nature of a polymer. Poly means many; thereby a polymer is a compound built from many other compounds. Specifically, those compounds are called monomers and as it applies to this discussion, these monomers are formed from common hydrocarbons. Yes indeed, that means volatile gasses and liquids. As an example the basic hydrocarbon ethane can be made to repeat its base molecular structure- many thousands of times to form an enormous chain (speaking to the relative scale) that effectively entangles with neighboring molecules until the new material becomes a very strong solid. The common polymers are composed of very few elements; predominately carbon and hydrogen. We also find oxygen, chlorine, and nitrogen as small constituent parts of these compounds. There is a growing branch of material science that deals with something called a fluorocarbon. Fluorocarbons are manipulated to build fluoropolymers. These relatively new materials are still being discovered and explored. They promise strength and resistance that far exceed our current and common hydrocarbon polymers. These high-performance materials are the real future of polymer science. We should expect to see this stuff employed more and more in the near future. Hold your breath for the fluoropolymer pistol.

Material scientists can tailor a polymer’s properties to fill an exact requirement. If the material needs heat resistance, there’s a monomer structure for that. If a material needs increased elasticity, there’s a monomer for that. If a material needs resistance to stress fracture, there’s a monomer suited to impart that quality. The custom tailoring is performed by carefully manipulating of the way these elements combine. The subject may seem to be high science, and indeed it is, but the basic process can be well understood with the application of some Google. It’s an interesting field and its worth some study and familiarization.

Those gun companies that have ventured into non-metal construction have implemented technology beyond the basic polymer. These materials have been combined with small fibers or particulate of glass, carbon, or even certain minerals. Short fibers or particulate elements are evenly dispersed into a polymer to form a homogenous solid. This is known as “filled” polymer. This type of material generally does not give up any of the strengths and properties of the polymer to make room for the filler. The filler may be included to mitigate some inherent weakness or deficiency of the polymer. The filler may be used only to make the structure less dense, and thus, lighter. Most often, filling a polymer with an additive is done as a means to increase strength, hardness, or resilience. Sometimes polymers are filled with materials that have lubricating qualities to reduce operating friction on wear surfaces. Some polymer structures have even been infused with evenly distributed air bubbles to create structured rigid polymer foam. Though, not a filled polymer, the integration of air bubbles demonstrates how specifically these materials can be manipulated and improved. Filled polymers are cheaper to produce than machined metal, and are adequate for low to moderate load and wear surfaces. Polymer pistol frames are cast or molded into their final detailed form in a single step- a step that only takes a few seconds. This is the process used to create the frames of the HK, FN, Glock, XD and M&P pistols.

Though it was the first to claim broad commercial success, and still remains the front runner in the market, the Glock was not the first polymer framed pistol. Heckler and Koch released a polymer pistol almost 13 years before we ever heard of Glock. Almost 57 years ago, we saw the first rifle built on a polymer receiver- a .22 rifle from Remington. The proliferation of polymer framed firearms is proof that this technology is a good thing. The exact polymer recipes used by manufactures are tightly guarded industry secrets. Though, some authoritative independent research has been conducted to uncover the mystery of the exact composition of at least one of these guns. The Glock pistol frame is made of a type of nylon- that is easy to demonstrate. But even with the required lab equipment and some understanding of spectroscopy, we can only approximate the actual formula. Whatever be the details, we know that the Glock is a close cousin of stain-resistant carpet. The commercially present polymer that shares much with Glock DNA is called Nylon 6,6. We know that Glock has further manipulated the formula of Nylon 6,6 to increase its strength and hardness. Unique to Glock’s formula is an integrated fibrous, crystalline texture throughout the frame casting- though the Glock frame is not actually a “filled” polymer. The apparent fibrous structure is engineered into the polymer itself. Glock’s frame material makes a proud demonstration of our grasp and abilities in material sciences and engineering.

Given the similar requirements of all polymer pistol frames, we can assume that all firearm engineers have chosen similar polymer formulas. One feature common to all polymer framed pistols is the tendency of those frames to utilize an internal metal structure. Some feature a molded-in steel skeleton. Some just use removable metal structure that nests into the polymer frame. Both of these measures are affected to offer reinforcement at high-load and high wear areas. Filled polymers are found in long arms as well. Any designation of an item as “synthetic” usually refers to a rifle or shotgun stock that is made of a filled polymer. These materials are more resilient than wood- sometimes even considered indestructible. They are generally featured on entry level or “working” class rifles and shotguns. Long guns clad in polymer or synthetic furniture give up all points of luxury to remain totally utilitarian.

The other branch of non-metal construction involves layers of fabric woven from precisely oriented long fibers of glass, carbon, aramid, or spectra encapsulated and bonded by a polymer resin into a solid form. Aramid and spectra fiber are true polymers. Carbon fiber, though nearly 100% structured carbon atoms, begins life as a polymer film. The bonding or laminating resins used to encapsulate these fibers are also polymer, though of a special class. In theory, these thermosetting resins form one contiguous polymer molecule of the entire cured structure. The winning attribute of fiber materials like carbon and aramid is that they do not stretch- or they do, but very little. This means that a solid form made from these materials is very resistant to any change in shape. This type of structure, where linear fibers are encapsulated in a binder is known as “composite” structure. Composite manufacture boasts performance properties that far exceed the constituent parts. Though fiberglass had been popular and successfully used by gun manufacturers for many years, it has been outclassed by carbon fiber fabrication.

There are only two good reasons for carbon fiber’s popularity: it is impossibly strong and its visual appeal is timeless. As to the strength, it can bear loads and endure temperature fluctuation that could cause steel or aluminum to deform and fail. It nearly matches the strength of steel and aluminum at a fraction of the weight. This makes it good for shooter comfort. Its rigidity is far superior to that of steel and aluminum. It is less harmonic than most metals- that is, it does not propagate vibration. This is good for accuracy- as in repeatable and reliable day-to-day and shot-to-shot consistency. Composite manufacture, as it applies to gun manufacture, is usually used in high-power rifle stocks and barrels. The rifle stocks of McMillan and Manner’s are created using composite construction. The rifle barrels of Christensen Arms, Magnum and Proof Research marry carbon fiber with steel rifle barrels.

Composite construction is a very expensive and time-consuming method of construction. Complex machinery may be employed to wind fibers into a perfectly calculated pattern. Swatches of fabric are laid into a mold by hand to ensure proper alignment to achieve peak strength and beauty. Composite structures are cured for many hours under high pressure in massive ovens. Painstaking preparation, processing and finishing are required but the performance and appeal of the finished product is unmatched. The presence of bare carbon fiber garners envy at the gun range. The hypnotic weave of carbon textile or the random illusory texture of a filament wound structure adds a degree of interest and refinement to normally ordinary things. It’s inspiring and pride-inducing.

Healthy capitalism demands that all things meant to be sold should be accompanied by a fair supply of hype. The gun market is not immune to this tendency to exaggerate. Some manufacturers have labeled their filled polymer receivers “carbon fiber” and some even call simple plastics “high tech polymer.” All polymers are, generically speaking, forms of plastic, but all plastics are not polymers, and all polymers should not be considered high performance. A milk jug is made from polymer- with much science and study behind it. But it is neither high-tech nor high-performance by all standards. And when a manufacturer calls their product “carbon fiber”, it had better be made of laminated woven textile or filament wound. Both of these are easily identifiable by their unique appearance. A receiver made of an homogenous gray plastic is not carbon fiber- it is likely just a filled polymer. Even if carbon is used as filler, that material should not be described as carbon fiber. The consumer should be wary of fancy titles applied to the material from which a gun is made, and pay attention to the quality of what they can see and feel and know on their own. The overstatement of the facts is all too prevalent by advertisers­ and manufacturers. But we can also observe the modest understatement of facts as they apply to the capabilities and features of polymers. Most shooters don’t know that a Glock’s frame won’t melt until almost 500 degrees. Many shooters don’t believe that some polymer frames and stocks are totally chemical resistant- despite the existence of special cleaners made for “synthetic” firearms. Some just don’t believe the claims that the modern filament winding process used to replace some of the steel on rifle barrels, and the space-age resin used therein, can actually exceed steel’s tensile strength and heat-sinking abilities. Of course, this kind of peak performance asks that the barrel manufacturer exercise great care and attention to detail and perform exhaustive quality checks during and after manufacture. There are definite and distinct advantages to using new technologies in the gun market. Not all new trends should be immediately relegated as heresy. Excellence is possible, however not guaranteed when utilizing hi-tech materials. Be assured that there are indeed some promises and sales pitches that are simple farce.

One must not expect nor accept that a gun company can just replace some parts with carbon fiber or polymer structures thereby improving quality or performance of a gun. Any and all advantages afforded by the use of non-metals demand that the gun be re-engineered specifically to fully exploit a new material’s capabilities. Beware the polymer “version” of a pre-existing all-metal gun. One thing to be sure of, is that time will march on, and material science will open new possibilities. Guns will use metals less and less, and at the same time get stronger, lighter, and more efficient.

By David Lake

Aluminum

Second only to steel, aluminum is one of the most common metals used in construction, architecture, and general industry. The metal was first extracted from its ore in the first quarter of the 19th Century. 70 years would pass before aluminum alloy became economical enough to exploit its tremendous qualities of high strength and low weight. In its pure form, aluminum is soft and ductile- of little to no use as a structural material. It is highly reactive- that is, it easily interacts with and forms bonds with other materials. For this reason it is never found in nature in its pure form. Most commonly, aluminum ore presents as an oxide or silicate. In fact, aluminum is the most prevalent metal in the Earth’s crust. Aluminum can be recycled and repurposed indefinitely. If it can be said that the modern world is built on Steel- it must be said that the world moves forward on aluminum.

Everything that can be made of steel can be made of aluminum- by all modern standards and methods of manufacture and engineering. Aluminum can be formed and machined and otherwise worked as any other ductile metal can. The newest aluminum alloys claim a higher tensile strength than steel. There is even one particular type of aluminum that can best 6AL-4V titanium in most criteria- strength, weight, cost, and machinability. With all its boasting, Aluminum does fall short of other materials in some capacities. For starters, aluminum cannot offer the same resistance to heat as steel. High temp aluminum alloys exist, but they cannot approach steel’s 2500 degree melting temp. Aluminum enjoys only a relatively narrow temperature threshold where its strength and resilience remain useful (at the extremes of cold and hot, it becomes brittle and weak). And aluminum cannot endure the levels of abuse and mechanical stress that steel may take in stride. Aluminum tends to be slightly less forgiving than steel when pushed close to its limits of operational loads. It is indeed very strong per given mass- stronger than the same mass of steel. But while steel is tends to be elastic; aluminum behaves more like a plastic. That is, aluminum can be stressed only so far until it reaches its point of deformation- from where it cannot recover.

Aluminum only became a viable structural material post 1900. The early use of aluminum-copper alloy was seen in the frame construction of airships. Post World War I, heat resistant aluminum-nickel alloy would be utilized in the internal combustion engine and the (relative) high performance frames and engines of airplanes. Following WWII, aluminum alloy would be refined and specialized enough to find its way into jet engines. The aerospace industry would eventually become synonymous with aluminum- the terms “aluminum” and “aircraft alloy” would become generic synonyms. While the air and space industries do indeed employ aluminum structures, they clearly do not hold exclusive rights to the discovery or its purveyance. Be not be swayed by marketing strategies that use fancy descriptions like “aircraft aluminum” to sell a product. It is by common sense and logical conclusion that almost every industry has adopted aluminum to improve just about everything- gun manufacturers included. By 1949 Colt would announce a variant of the 1911 with an aluminum frame. Weight savings was the idea. Smith and Wesson would soon follow suit with semi-auto pistols and a few revolvers. Colt answered back with an aluminum snub-nosed wheel gun. Late in the 1950s, Europe would revisit its staple handgun designs with aluminum variants. While at the same time in America, some inspired aircraft engineers would put their heads together to create the AR-10. Some designs, as is the case with the AR-10 and AR-15, could only be possible with aluminum construction. Aluminum finds its purpose in firearm design right between steel and polymer. It matches the strength and approaches the durability of steel, while shedding much of the weight (lightweight is becoming more than a fad in small arms design). Hence the proliferation of polymer guns today. Aluminum is almost totally resistant to environmental and chemical attack- steel is not. And aluminum won’t distort or warp at elevated temperatures- which has been known to ruin a polymer-framed pistol.

As to the application of aluminum to the firearms industry, there is only one group of alloys- and within that, 3 “series” that will be encountered. That group is known as heat treatable aluminum. The alloys of direct interest and application to the gun industry will be any of these three series; 2000, 6000, and 7000. Each comes with its own set of benefits and deficits. Proper alloy selection should satisfy physical, chemical, and environmental requirements. Adverse operating forces and environmental factors encountered by a firearm are many. Most obvious would be the extreme pressures and stresses created by firing a cartridge. A gun’s mechanism may apply and divert and share and shed loads across multiple vectors and surfaces and structures within a single momentary stroke of the action. A firearm creates high heat and caustic or otherwise reactive byproducts during the ignition and combustion processes. A firearm requires routine cleaning and lubrication which means regular exposure to chemicals and substances. And a gun may be required to operate in extremes of temperature and humidity and salty or dusty and abrasive environments. One other noteworthy detail is the condition or temper of an alloy. This “T” designation describes the heat treatment and process a specific alloy has received. As the 4 digit alloy code describes the chemical makeup and suggests the general use, the letter code accurately describes that material’s specific capability. The most commonly known is T6. This heat treat condition can be applied to almost any 2000, 6000, or 7000 series alloy.

Heat treatable aluminum alloy can be manipulated or “tooled” by several means. A wrought solid (aka: billet) can be machined or cut into final form, or a final structure may be forged or drawn. A casting may also provide a lump of material that will need to be machined into tolerance. An exciting growing industry of “additive manufacture”, also known as 3D printing or (similar) laser sintering can also be used to form aluminum into a finished product. New material science and manufacturing processes are always evolving. Of interest is that one unique company is even using explosive energy (something close enough to RDX) to weld aluminum to steel substrate to create molecularly bonded dissimilar bi-metal pistol frames. One of the newest and greatest aluminum alloys known as Tennalum is stronger than most steels (in annealed state) and lighter than titanium of the same strength. Aluminum’s properties make possible certain structures and mechanisms that would be otherwise impossible. These miracles can be performed at reduced manufacturing expense compared to steel or titanium. Aluminum is easier to work and less taxing on manufacturing tools and equipment. Copper, manganese, silicon, zinc, magnesium, chromium, lithium, zirconium, iron, nickel, titanium and now scandium are all used to make specific aluminum alloys. Strength, hardness, elasticity, ductility, conductivity (both electrical and heat), and density are among the attributes that can be manipulated and prescribed to fulfill specific material requirements. The additive trace elements essentially imbue aluminum alloy with advantages over, and immunities from distinct physical, chemical and environmental influences.

One will likely not find an aluminum slide on a center-fire pistol. A slide contains locking lugs and other highly stressed structures. The receiver of a bolt action rifle should never be encountered in aluminum. A gun’s barrel must assuredly never be made from aluminum. And trigger parts can’t be made from aluminum either. It’s a great material- but it is a structural material. Aluminum cannot be expected (generally speaking) to repeatedly endure high wear or heavy impact. Aluminum pistol frames and AR-15 receivers house the internal workings and make interface with the locking surfaces and wear components. Pistol frames and AR-15 receivers are usually made from a 7000 series alloy- which can be as strong as some steels. These alloys can endure repeated light impacts, as is seen in the AR-15 buffer. If properly treated on its surface, or coated with a hard or lubricious coating, aluminum can ( to a degree) excel as a wear surface against opposing, moving components, as is seen in the lightweight and long wearing frames of Beretta, Sig, and some 1911 pistols. Alloys of a 2000 series designation match the strength of 7000 series; though the 2ks feature different alloying elements to adjust the metal’s chemical properties to meet more specialized applications.

The lesser alloy discussed here, known as 6000 series, are utilized in gun construction also. The fact that the material is not at the top of the list for achievement should not foster skepticism. Trust that any manufacturer has done the homework to make competent and confident decisions as to material selection. The performance of high-grade 7075 can in fact be matched by medium grade structural 6061- simply by the addition of more material. To reiterate, 6061 is not incapable of performing 7075’s job; it just takes more 6061 to do it. That should be acceptable to most of us who recreate with our guns on the weekends. There is only slight risk to accept when choosing a gun that includes 6000 series components. 6000 alloy might scratch, or dent with some entry-level abuse. Again, this should not give pause as most of us spend our own hard-earned dollars on our guns and intend to protect them from damage and abuse. Guns and components made of 6000 alloys might be identifiable by a thicker, heavier profile.

Once upon a time aluminum was in fact worth as much as gold. Today it is relatively cheap, but is used to make anything that must demonstrate a level of excellence. It is used as armor in vehicles and aircraft. It is used to form the structures of spacecraft; and also used as fuel to launch those spacecraft. Aluminum is diamagnetic; a property that makes aluminum the ideal material to be used as the “bullet” in next wave electro-magnetic artillery- called Railguns. And of course, the modern small arms industry we enjoy is only made possible by the judicious application of aluminum and progressive ideas of how to apply it to effect solutions to engineering problems. There is undoubtedly more new development to come. Years ago, the introduction of aluminum pistols and rifles garnered some enmity from the informed consumer. But science and experience healed that rash for most. Perhaps aluminum will usher in the day when steel is considered a substandard and inferior material from which we used to make guns.

By David Lake

Steel, Simplified.

Steel is the stuff of which the modern world is made. It is pervasive in history and its presence and application mirrors the rise and fall of man and his kingdoms as well as his proliferation around the globe. Scientists and engineers of the past century have been largely unsuccessful at creating its replacement. Barring the limitations imposed by the basic laws of physics, there are not many problems that cannot be solved by the judicious application of steel in one of its many forms. There is perhaps no better example of Mankind’s technological triumph than when he used steel to create the gun.

The oldest known “gun” by todays definition was developed in China (agree most anthropologists and archaeologists). The first guns created by the ancient Chinese were likely bamboo- or other hollowed out wooden tubes, which may not have been used to fire a projectile. There is some conjecture that these guns were first implemented as “shock and awe” technique- firing off bursts of flame and smoke to intimidate and confound a battlefield foe. It is unclear when exactly the gun would be used to fire a projectile- which was likely an accident the first time it happened. Man’s inherent need and ability to fix and improve things around him would ultimately adapt the simple pyrotechnic display into an implement crafted from steel, and intended to fire a projectile. The rest of the story of the gun follows man through the middle Ages, the time of exploration and conquest, and ultimately the industrialization and modernization of manufacturing and the globalization of commerce. There are marked times, usually times of war that spawned the great advancements in the science of the gun. Mounted cavalry, siege weapons, personal body armor, cannon and naval warfare all demanded that the gun become more potent and precise. Distance and accuracy and power would become requisite qualifications of the gun. Sometime in the last 500 years, the science of the gun seems to have reached a plateau, relatively speaking. Every shooter from a matchlock pistol to a shore gun battery would be made of steel (as they still are). Steel could provide the strength to exploit the power required to inflict the ranged effect we associate with the modern firearm.

The meter of the modern small arm often and deservedly defers to the “mil spec.” This is an established code of standardization. It envelops a set of rules and requirements for anything claiming to be up to par. It is not necessarily a qualifier of excellence or superiority- unless superiority can indeed be found in uniformity and consistency. The term “mil-spec” has become a generic descriptor, and is often applied to any of the wares and materials purveyed by today’s arms makers. And it is not entirely incorrect to refer to a steel alloy applied or used per an established mil-spec as “ordnance steel.” It is widely agreed that ordnance, or mil-spec steel refers to a specific family of steel alloy; chrome-moly, such as 4140. The enforcement of standards and uniformity is absolutely necessary to ensure any amount of quality and reliability in any system. Today all metal alloys are given a title or numerical designation from one of the authorities on metallurgy and engineering, the SAE, and AISI. These material names and designations describe a recipe or physical and chemical properties. So a steel may be described by what it actually is, as is the case with 4140CM steel, the 4 digit label indicates general type of alloy, and the precise levels of other additive elements to make the steel.

In actual terms, depending on the manufacturer of a gun or its components, the terms Mil spec and Ordnance Steel may be used to describe any of the following (but not limited to); 4130, 4140, 4145, 4150, 4320, or 4340 chrome moly alloys. The truth of the fact is that ANY steel may fall into the category of being “mil-Spec” provided that it satisfies the criteria set forth in the military standard for operating and yield strength for a specific application. There is a tendency for gun manufacturers to use misleading descriptions of their steel and its capabilities in order to promote sales. All steels are not created equal. This sales tactic can put the gun and its user at risk. All steels are not created equal; beware of the fly-by-night startup gun company that professes tactical supremacy but omits the metallurgical details of their operation. That said, modern firearms components from reputable sources (as are most things engineered) are designed with a “safety factor” in mind. Any gun barrel today should be designed with a minimum 1.5 safety factor- which means that barrel is designed to endure 1.5 times its intended operating load before failure or fatigue. The “mil-spec” for a steel structure usually demands a factor of only 1.5. Commercial engineering often requires a safety factor of 2.0 or higher. One should also be wary of the claim of “aerospace” in firearms design. The tolerance, safety factor and quality assurance by aerospace standards all become prohibitively expensive and ultimately restrictive to the end user. Aerospace grade demands a total detailed and documented control and trace of material from creation through use and operation. Nothing about your rifle is aerospace grade.

On to the specifics of the steel that may be encountered in the modern small-arm. There are only 4 general types of steel; carbon, tool, alloy, and stainless. All material that can be described as steel is one of these. The creators of steel add various trace elements to iron to achieve desired properties. All steel contains between .25% and 2.5% carbon, which allows the base iron to be chemically or thermally manipulated with or without the addition of other alloying elements. To earn the rank of stainless, the recipe of that steel must contain at least 11% chromium. Chrome moly alloy steel does contain chromium, but not enough to be stainless. And all stainless steel is not totally rust resistant. Some stainless is highly magnetic. It is doubtful that one will encounter a low carbon or plain carbon steel on a gun today; industry lawyers and a general concern for safety have well established a minimum for safety standards. Tool steel is capable of being very hard and tough, but is more difficult to craft. It may be used on guns in small amounts to form items like trigger parts or lock components. One should expect to find all (non-stainless) gun barrels and receivers to be made of an alloy steel; nickel-steel, nickel-chrome, or chrome-moly steel. These types of steel contain trace amounts- usually only up to 3% by mass of these other elements. The presence of nickel imparts extra strength and tremendous resistance to temperature and mechanical stresses. It is interesting to note that iron meteorites are usually an iron-nickel alloy- containing up to 25% nickel. That high nickel content is responsible for the meteorite’s ability to survive entry. The presence of chrome and molybdenum in steel alloy will increase hardness and resilience. Plain carbon steel is too weak and brittle or soft for firearms application. Chrome moly steels are not resistant to oxidation and other surface reactions to include rust and corrosion. Gun parts commercially produced from chrome moly steel are always encountered with a coating or treatment to inhibit surface corrosion. The most common are blueing and parkerizing which form protective oxide barriers on the steel. Chrome moly steel may be coated, clad, or plated in other metals like electroless nickel, hard chrome or newer high performance metal/polymer matrix coatings.

Chrome moly steel is indeed the first choice of the professional market. It is tough. It maintains strength and stability over a wide temperature range. It resists fatigue and failure caused by abrasion, wear and heat. Even in hostile maritime environments, today’s material science offers a host of treatments and coatings to protect the steel from surface attack. Chrome moly used in ordnance is not a “free machining alloy”, that is, it is difficult to machine and form. However, chrome moly does lend itself well to the application of these aforementioned coatings and surface treatments. We are all familiar with “chrome-lined” barrels. Most all gun barrels in general circulation with our armed forces- pistol and rifle alike are chrome lined (M-16 rifle, M9 sidearm). Adding a layer of abrasion and heat resistant hard chrome to the interior surface of a barrel adds longevity. In the case of the M16 or AR-15, if it is respected and not abused, a chrome-lined, chrome-moly steel barrel can expect to serve its owner with good function and acceptable accuracy up to or beyond twenty thousand rounds.

Stainless steel is rapidly becoming the default material used by barrel manufacturers. The most common alloy used in the gun market is known as 416R. This stainless steel makes an attractive barrel to be sure. It’s bright and shiny, and is known for being easy to machine. 416R is a “free machining alloy” which implies that it is created with a molecular structure that makes the material easy to cut. Free machining alloys employ trace amounts of lead and sulfur to improve machinability. While making this steel cost effective to manufacturers, and visually attractive to the consumer, the mechanical properties of free-machining alloy may also make it less desirable to the well-informed. 416R is not nearly as abrasion resistant as chrome-moly steel. And it can only claim 65,000 psi tensile strength (4140CM boasts 98,000psi). 416R does not resist fatigue and erosion from exposure to high heat. At high heat levels- those commonly encountered in military applications, 416 can distort, lose its heat treated state, and even de-alloy—a condition where the additive materials lose their microscopic bonds to the iron/carbon structure. So this material, while in use, could become unsuitable or even unsafe. Not to worry—416R comes with a reliable programmed response to imminent failure. It will split like a banana peel before it fragments. This splitting action is resultant of the “stringers” as they’re called, the areas of sulfur that co-mingle in-between the regions of martensite (crystalline structures) in the metal alloy. There are other grades of stainless one might encounter in barrel making. 410, 420 and 17-4 are less common, though they are found in use. 17-4 is renowned as a super alloy. It is fabled to get stronger from heat exposure. It has been said that it possesses mystical powers to “self-heal” micro fractures and surface defects. Few have ventured to deep-drill and cut rifling into a chunk of 17-4. Many have failed. The name Noveske will forever be remembered as one that succeeded. 17-4 is mainly used in pistol and revolver frames, muzzle devices, or small parts and even receivers and bolts of custom high-end high-power rifles. The last stainless worth mentioning here is 410 alloy. It is the underachiever of the bunch. The yield of this material is actually less than its intended operating threshold- a fact that some in the industry will argue. 30,000 PSI is where 410 can undergo “plastic deformation,” that is, be stressed past its ability to bounce back. Barrel makers still use this stuff knowing that a 5.56 NATO cartridge reaches over 60,000 psi just after ignition. Is this cause for alarm? Not really. Stress is calculated as a constant applied force. The pressure curve inside a gun barrel in not contained for any period of time, nor at a static load, but rather a burst that reaches a peak pressure. The pressure is not contained long enough or focused at a singular point where it could cause damage to the barrel. The barrel is saved by the fact that high pressure gas acts with equal force on all sides of its container (in this case the barrel)- and one side of the container (the bullet) is moving away from this applied force. So the bullet is effectively a valve that allows the pressure to escape. 410 alloy is said to be tougher and more abrasion resistant than 416. It is used by some manufactures to make gun barrels to save cost as it is imminently easy to machine. The more common stainless, 416R does deliver on some promises. Many custom rifle builders who work for the competition market trust 416R. Countless benchrest, palma and F-class records have been claimed by guns fitted with barrels made from 416R. This material does in fact make for a perfect surface finish during machining. This perfect surface lends itself to superb accuracy. A barrel properly ‘smithed from 416R will perform supremely, though not indefinitely. A match-grade stainless barrel fit to a high-powered competition rifle may be expected to have a good service life of 3000 rounds, more or less, depending somewhat on the caliber of the rifle, and largely on how it is cared for.

Steel of any alloy may be encountered in a number of “states.” This refers to the condition of heat treatment it may have received. Annealed steel has been softened. This condition does not imply that the steel is mild- only that it has been reduced to a softer state to make it more workable. Hardened steel generally refers to a surface hardening to improve that steel’s wear resistance or reduce its frictional coefficient. This condition may also be called “case” hardened. Heat treated steel is generally hardened throughout, also known as “core” hard. Core hard is a condition commonly employed on high wear or high load components. Certain alloys are better suited to be case hardened. Others are tailored for use in core hard applications. For example, the bolt carrier group in an AR-15 is made of several steel alloys- each selected for it properties as they fulfill the requirements of the BCG’s operation. The bolt itself may be made of something called Carpenter 158 that has been heat treated to a desired surface hardness to resist wear while maintaining internal elasticity, and resistance to fracture of the locking lugs. The bolt carrier body is commonly made of core hard 8620- a nickel-chrome-moly steel used for its superior resistance to heat induced fatigue and mechanical shock. The carrier houses a high-temp expansion chamber that is usually hard chrome plated. The gas key might be made of 4130CM, and specially coated to resist high temperature and impart lubricity so as not to cause abrasion to interacting surfaces. The cam pin receives tremendous abuse, and is formed from a core-hard piece of 4340CM—very high in nickel and chrome. The cam pin will endure severe abuse- repetitive compressive and shear forces and high heat imparted by the M-16’s operating system. These parts are often protected by a hard metal plating or clad in a metal/polymer matrix. Both, designed to kill friction and resist heat’s damaging effects.

So we can conclude that there is no “best” steel for your gun. Lesser materials may be used to great result provided proper engineering and quality assurance to back them up. Super alloys can lose all their attraction when cost and gained advantage are brought into proportion. Long past are the days of Damascus steel when one could be killed by his own gun if the bi-metal structure were to give way. The quality and consistency of steel used in the industry today exceeds the quality of manufacture implemented by the gun makers themselves. Our modern steel industry is nearly flawless. Good steel makes us better.