Many consider Glock the standard by which fighting pistols are held based on capacity, weight/firepower ratio, ruggedness, and reliability. A new product from FAB Defense in Israel and currently distributed in the U.S. by the Mako Group seeks to capitalize on these positive traits with the KPOS Glock-to-rifle conversion stock. The KPOS aluminum stock chassis transforms a Glock handgun into a viable personal defense weapon (PDW) category.

The KPOS was designed with personal security details and covert operations in mind, especially if the Glock 18 machine pistol is utilized. The KPOS arrives with Picatinny style rails along the top, sides, and bottom allowing for performance enhancing accessories such as vertical forward grip, optic/red dot sight, flashlight, or laser aiming device to be mounted. The aluminum framed KPOS stock features a side folding stock that further reduces the weapon’s footprint when folded. The KPOS measures 13.5 inches with stock folded and 21.5 inches with stock deployed and weighs less than 4 pounds with a Glock 17 mounted. For comparison, a Glock 17 installed in the KPOS is smaller and lighter than a mini-Uzi. The KPOS unit tested works with Glock 17 and Glock 19 compatibles (G17, G18, G34, G22, G35, G19, and G23). Other KPOS models for SIG Sauer and Springfield handguns are expected.

In the U.S., the KPOS converts your Glock pistol into a Short Barreled Rifle (SBR) classification and must be treated as such with an approved Form 1 from the BATFE before you possess this stock and install a weapon in the KPOS. Failing to do so is a violation of Federal law with extremely serious consequences that may result in fines and/or imprisonment.

The KPOS stock arrives in a hard case that includes folding forward vertical grip, modified Glock slide back plate for charging handle adaptation, and detachable single point sling. The patented KPOS design locks both the front and back of the Glock into the KPOS frame without requiring any tools. The Glock’s railed dust cover is used as an attachment point in the front and a simple wedge block in the rear secures the frame. This prevents the pistol from moving ensuring reliability and stable point of aim. The Glock’s back plate located at the slide’s rear is switched out with a modified version enabling a charging handle to project out the KPOS’s left side for slide manipulation when installed in the KPOS. The Glock’s open sights are still accessible, though mounting a red dot or other type of optic is best for extending effective range.

Many will question the utility of employing a pistol cartridge in a shoulder fired weapon. Most engagements happen within a 100 yard range, especially in a civilian setting, with handling and reliability playing more of a factor in quick, reactive engagements than specific caliber used. Less experienced shooters will find the lower recoil pulse and muzzle blast of a pistol caliber fired from the shoulder easier to manage, which often times will translate into better accuracy.

A Glock handgun is transformed into a much more potent package when mated to the KPOS stock. A Glock17 using a Lone Wolf Distributors stainless barrel with threaded muzzle was mounted in the KPOS for this review. One note of importance here that once registered as an SBR, a weapon used with the KPOS is required to stay in this configuration and should not be used in other applications. The KPOS allows the mounting of a suppressor if a user desires. The barrel shroud is easily removed allowing for a suppressor’s diameter. The advantage derived from the Glock KPOS SBR is that effective range and shootability is increased compared to a handgun; thus the PDW reference at the beginning of the article. This is based on the KPOS’s multiple points of contact when interfaced with the shooter. This consists of shoulder, cheek, and hands spread further apart for more stability compared to when handling a handgun.

The KPOS’s rail system maximizes potential with accessories such as an optics, lights, lasers and vertical forward grip. The vertical foregrip has fast become a standard accessory on any rifle or carbine equipped with a forward accessory rail. The increased leverage and control offered by the vertical foregrip aids in weapon manipulation and stability when firing. An Aimpoint H1 and Insight Technology M6x Tactical Laser Illuminator were added to the KPOS’s rails.

The Glock 17 used in conjunction with the KPOS conversion was a proven performer with upwards of 4,000+ rounds fired without issue. Importantly, the Glock maintained its reliability once installed in the KPOS. Installation is accomplished by first turning the KPOS upside down. Towards the back of the stock located near the folding stock hinge point is a pin. Remove this. This allows you to next slide the metal retaining plate out the back. After this, insert the Glock all the way towards the front where there is an interface between the Glock’s dust cover and the KPOS that locks the front of the Glock down. Make sure the Glock’s front dust cover side rails slide into the KPOS unit before turning the locking mechanism located on the side towards the fully engaging the dust cover’s cross slot. If done correctly, the GLOCK should not be able to move at this point. Slide the metal wedge plate up against the Glock’s rear frame and reinsert the pin.

A wide range of 9mm loads were tested including 115gr, 124gr, and 147gr JHP and FMJ loads from Black Hills, CCI, Federal, Hornady, Remington, Winchester, and Wolf. The Glock KPOS SBR was sighted in 1 inch high at 25 yards, which gives an approximate 50 yard zero and 7 inches low at 100 yards trajectory depending on exact ammunition used. This is a flatter trajectory than most would expect. The decision to utilize the threaded Lone Wolf barrel is a nod to future plans to incorporate a suppressor with the Glock KPOS SBR as 147gr 9mm is an obvious choice for use with a suppressor. Range evaluation consisted of a mixture of drills establishing durability, reliability and handling. Firing behind cover, engaging multiple targets, magazine changes, targets at CQB distances to 100 yards, and off-shoulder shooting made up the bulk of these drills. Rounds fired during T&E quickly rose to over 800 with only a few range visits as it was too tempting to keep feeding in the Glock magazines. No failures were experienced no matter how quickly or how many 33-round Glock magazines were fired. This is a credit to both Glock and the KPOS chassis being well designed as to not interfere with the mounted weapon’s functioning. Purposely induced malfunctions were cleared in the same manner as one is accustomed to with a Glock thanks to the side charging handle and operating controls not being compromised with the KPOS stock chassis. A large portion of the Glock slide and ejection portion is not obscured, which further assists in no reliability issues.

The compact size of the Glock KPOS SBR cannot be overstated. A DeSantis DSD shoulder holster rig was tested as one carry method. It is not being represented that the KPOS SBR is a substitute concealed carry weapon in lieu of inside the waistband carry. However, the DSD rig proved a viable carry method under certain conditions. The KPOS chassis with stock folded is smaller than a mini-Uzi and rides under the user’s right arm with multiple 33-round magazines carried under the left arm. Many would favor discrete off body carry of the KPOS SBR in a back pack or attaché/briefcase with another 9mm Glock handgun carried concealed thus offering advantage of same caliber/magazine interchangeability. The availability of proven Glock factory 33-round 9mm magazines is huge advantage for the Glock KPOS platform. The increased capacity represented by the 33-round magazines should not be underestimated compared to other non-9mm calibers within Glock family, not to mention other manufactures as a whole. The KPOS’s folding stock is quick to deploy and sturdy once unfolded in the shooting position. The two-handed grip afforded by the KPOS’s vertical forward grip combined with Aimpoint H1 red dot sight picture is more than adequate reacting to a situation until the stock can be deployed.

In an effort to determine the advantage of mounting a Glock in the KPOS, the Glock that was installed in the KPOS was fired in its pistol configuration at 15, 25 and 50 yards at a plate rack featuring multiple 6-inch round targets. This was an effort to establish a baseline of field accuracy with shooting done standing unsupported. The Glock was then installed in the KPOS and fired in the same format. The accuracy and increased time differential in falling the plates definitely supports the advantages offered with the incorporation of the Aimpoint H1 red dot sight and ability to shoulder the weapon. While plates were successfully engaged at 15 and 25 yards with relatively few misses with the Glock in its original form, 50 yards was challenging with results less than satisfying. The KPOS Glock SBR proved much faster at 15 and 25 yards with 50 yards hits routine thanks to the shoulder stock and red dot sight. The Aimpoint H1 red dot sight assisted in engaging targets at close distances with the red dot easy to pick up rapidly, while at the same time increasing accuracy out to a hundred yards far beyond normal open sight capabilities. Handguns can engage targets at ranges much further than most realize, but this is not the norm and often under pristine conditions with plenty of time to set up. The Glock’s consistent trigger pull, controllable light recoil, firing from a closed bolt, and minimal muzzle blast, further accentuates this accuracy advantage. The muzzle blast differential between a 9mm carbine versus obnoxious rifle muzzle signature is further accentuated in confined spaces such as inside a home if serving in a personal defense role. The old standard touting the advantage of having both a carbine and handgun chambered in the same caliber should not be casually dismissed, especially if an organized logistics chain cannot be counted on. The Glock 19 handgun resting in the holster on your hip can also utilize the 17 or 33-round magazines used with the Glock 17 in the KPOS slung around your neck or resting under your arm in the DeSantis DSD shoulder rig.

Of late, it seems more Glock carbine options are appearing in the market. Few offer the total package of the Mako KPOS in terms of metal manufacturing, folding stock, ease of install/conversion, and Picatinny style rails allowing for easy adaptation of accessories. A pistol caliber carbine can never be compared across the board to a weapon firing a rifle round due to effective range and lethality of the pistol round versus a rifle cartridge. However, a 9mm carbine typified by a KPOS Glock SBR is not a weapon to be ignored. Beyond a doubt the KPOS Glock is much more potent than any handgun due to its increased effective range and shootability thanks to the ability to be fired from the shoulder. The ability to keep a PDW configured like the Glock KPOS will outweigh its limitations in many people’s minds. The KPOS converted Glock is substantially smaller than several other SBR rifles it was compared to consisting of AKSU-74 Krinkov/Suchka, 9mm AR, and SIG556. The KPOS Glock conversion’s portability to effective firepower ratio will trump a rifle’s power for many. The KPOS enhances the Glock handgun into a PDW with effective range over 100 yards via shoulder stability and sight enhancement options with the Picatinny style rails. The KPOS chassis seamlessly integrates the Glock. There is no compromise in handling or reliability with mating the Glock to the KPOS. A user has a just as positive feel with the KPOS conversion as one would with a dedicated PDW or SMG. A survey of the existing market will demonstrate few other matching weapon system options in terms of size, reliability, and capability as the Glock KPOS SBR, especially for the civilian consumer.

Sites of Interest

Mako Group
1 Lenox Ave
Farmingdale, NY 11735
(866) 753-9444
www.makosecurity.com

Aimpoint, Inc
14103 Mariah Court
Chantilly, VA 20151
www.aimpoint.com

DeSantis Holster and Leather Goods
431 Bayview Ave.
Amityville, NY 11701
(800) 424-1236
www.desantisholster.com

Glock
6000 Highlands Pkwy
Smyrna, GA 30082
(770) 432-1202
www.glock.com

Insight Technology
9 Akira Way
Londonderry, NH 03053
(866) 509-2040
www.InsightTechnology.com

Lone Wolf Distributing
57 Shepard Rd.
PO Box 3549
Oldtown, ID 83822
(208) 437-0612
www.lonewolfdist.com

The phone call from Carl Bertil Johansson in early summer 2009 came out of the blue. The founder of the Swedish company CBJ Tech had read an article I’d written about military Personal Defence Weapons (PDWs) for soldiers who do not normally carry a rifle. I had concluded that the optimum weapon configuration would be a compact machine pistol like the 9mm Brügger & Thomet MP9. I had also observed that the gun’s ballistics could be transformed by adapting it to fire the 6.5×25 CBJ cartridge. He thought this idea sounded promising so had contacted Brügger & Thomet, who were interested enough to supply him with an MP9 featuring a prototype barrel in 6.5×25 calibre. Initial testing had made him so enthusiastic that he was calling to invite me to Sweden to try the gun and ammunition combination for myself. How could I refuse?

The MP9

The MP9 has been developed from the Steyr Tactical Machine Pistol or TMP, to which Brügger & Thomet acquired the rights in the early 2000s. This innovative Swiss company has made a number of modifications, the most obvious being a side-folding shoulder stock, which transforms the steadiness of aim and the effective range. They have also added a NATO accessory rail on top for optical sights, ghost ring rear sights with an adjustable foresight, a trigger safety (similar to the Glock system), a suppressor attachment on the barrel sleeve (B&T also make the suppressors), and translucent magazines for 15, 20, 25 or 30 rounds. Options include a Picatinny rail under the barrel in lieu of the fixed handgrip, and a fixed skeleton rather than folding stock. The standard colour of the body is black but green and coyote tan are also available, as is a blue version adapted to fire Simunition FX training ammunition (which can also work with the new Force on Force cartridge recently introduced by ATK) and a red “manipulation” gun which cannot fire live ammunition and is used for safe handling training.

The result is an exceptionally compact and lightweight submachine gun or machine pistol, largely made from polymer and weighing just 1.4 kg (3.1 lbs) empty. Loaded 9mm magazines weigh 240 grams (8.5 oz) for 15 rounds to 440 grams (just under 1 lb) for 30 rounds. The MP9 is 303 mm (11.9 inches) long with the stock folded and 523 mm (20.6 inches) with the stock unfolded. Barrel length is 130 mm (5.1 inches). Unlike most SMGs (with the notable exception of the Heckler & Koch MP5 series) the gun fires from a closed and locked bolt, utilising a rotating barrel locking system; it will still fire when the muzzle is pressed against the target. The cyclic rate of fire is 750-800 rpm. The single shot/automatic selector and manual safety switch is a push-button by the thumb.

According to B&T, about 5-6,000 MP9s are sold every year. The gun is widely exported and is now in service with many special forces and close protection teams. The use of the ubiquitous 9mm cartridge is a significant selling point, along with the compact dimensions, the open holster (the gun clips into it) and the availability of the training versions. The modest penetration of 9mm ammunition isn’t felt to be an issue as hardly any of the expected opposition use body armour (this may not, of course, remain the case indefinitely), and around 50m is regarded as an adequate range for its particular role.

The nearest competitor to the MP9 is the Heckler & Koch MP7. The most obvious difference between them is that the MP7 is available only in HK’s unique 4.6×30 calibre, whereas the MP9 fires the 9×19 NATO, aka Parabellum or Luger, which is readily available from many manufacturers in a very wide range of loadings. At least, that was the case until recently, when the first example of the B&T MP9 in the 6.5×25 CBJ version appeared.

The 6.5×25 CBJ

Carl Bertil Johansson is an experienced gun designer who has worked with Aimpoint and SAAB Bofors among others, but set up CBJ Tech to develop his idea for a high-performance cartridge. The company, a family-run business, is based in southern Sweden and owns a Cold War bunker that provides very secure accommodation for workshops and range testing.

CBJ started development of the 6.5×25 cartridge in the late 1990s at the time of the NATO competition to select a new PDW round. This was intended to replace the 9×19 with longer-ranged ammunition able to penetrate NATO’s CRISAT target (equivalent to contemporary Russian body armour) at 150 metres. The only cartridges officially tested were the 5.7×28 FN developed for the P90, and HK’s 4.6×30 for the MP7. It proved impossible to reach political agreement on which to choose, so no decision was made.

FN and HK both started with “clean sheet” ammunition and gun designs, but Carl Bertil decided on a different approach, reasoning that a cartridge that was interchangeable with the universal 9×19 round by means of a simple barrel swap would have a much wider appeal. It would mean that existing guns could be adapted to fire the new cartridge, and also that guns in the new calibre could be easily changed to 9×19 if required; even the magazines remain the same.

This design principle meant that the new CBJ cartridge would have the same overall dimensions as the 9×19 (including the rim diameter) and would need to develop a comparable recoil impulse to ensure reliable gun functioning. The cartridge that emerged from this study was the 6.5×25, with an extended, necked-down case and a short bullet protrusion. Several different loadings in three ballistic groups have been developed.

To compete with the 5.7mm and 4.6mm rounds in meeting the NATO PDW long-range penetration requirement, a sub-calibre loading is used. The standard military “ball” loading is actually a 4mm calibre tungsten bullet in a plastic sabot. The bullet weighs 2 g (31 grains), 2.5 g with its sabot. There is a “spoon-tip” version designed to encourage more rapid bullet upset on impact, and a training variant using cheaper core material. All of these are fired at a muzzle velocity ranging from 730 m/s (2,395 fps) from a 127 mm (5 inch) barrel (the recommended minimum barrel length) to 900 m/s (2,950 fps) from a 305 mm (12 inch) barrel. The tungsten-cored loadings fired from a 12 inch barrel match the trajectory of the 5.56×45 NATO from an M4 Carbine and have much superior penetration to its standard SS109/M855 ammunition, being able to punch through 9mm armour plate. From a 12 inch barrel, velocity at 300 metres is 578 m/s (1,900 fps) at which range it will still penetrate the CRISAT target.

The 6.5mm version of the MP9 has the barrel extended to 150mm (5.9 inches), giving a muzzle velocity of just over 800 m/s (2,620 fps). By comparison, the 5.7×28 P90 and 4.6×30 MP7 both fire as standard 2 gram (31 grain) bullets at about 720 m/s (2,360 fps). A brass-jacketed 6.5mm ball round weighs 7.5 grams (115 grains) compared with 6.2-6.4 grams (96-99 grains) for the 5.7 and 4.6 rounds and around 12-13 grams (185-200 grains) for 9mm. Loaded 15 and 30-round 6.5mm MP9 magazines therefore weigh about 165 and 290 grams (5.8 and 10.2 oz) respectively. Steel and light-alloy cases are being considered by CBJ, but the initial emphasis is on brass.

The other ballistic groups fire full-calibre 6.5mm bullets. One group, primarily intended for police use, fires lightweight 2.5 gram (38.6 grain) bullets at the same velocities as the sub-calibre loadings. These consist of the HET (high energy transfer) brass bullet and a frangible (polymer/metal powder blend) version for use in training or when barrier penetration needs to be minimised. The HET will also penetrate the CRISAT armour target at short range, but these rounds are most effective within 50 metres as the lightweight bullets rapidly lose velocity. The third ballistic group has just one round – subsonic armour piercing – intended for use with a suppressor. It is much heavier than the other bullets at 8 grams (123 grains) and can also penetrate the CRISAT target.

The 6.5×25 cartridge cases were previously made by reforming 9×29 Winchester Magnum brass, but CBJ Tech now has cases specially made for them. These use slightly thicker brass, requiring some adjustment to the propellant loads. The colour of the sabots has not yet been firmed up; originally these were black but this was changed to white to aid recovery from the indoor range’s backstop which has an outer layer of shredded black rubber. For production purposes, different colours may be used to indicate the loading.

SAAB Bofors was initially involved in helping to market the 6.5x25mm while the NATO competition was running, but is no longer involved with the project. CBJ Tech is continuing to develop the ammunition and demonstrate its capability in a wide variety of converted submachine guns and pistols. Those tested to date range from the Steyr AUG SMG to SIG Sauer and Glock pistols. Where necessary, pistols are fitted with barrels extended to 5 inches. A substantial purpose-designed SMG, the CBJ MS, was initially developed to use the new round and features a folding bipod and an optional large-capacity drum magazine in order to act as a light support weapon out to 400m. However, CBJ Tech is now mainly focused on adapting existing 9mm weapons, particularly the MP9 as this is seen as the ideal combination for the PDW role in which there is growing military interest. The remarkable performance of the 6.5mm cartridge, especially in armour penetration, is such that CBJ is intending to offer their conversions only to military and police customers.

How it Works Together: the MP9 in 6.5×25 CBJ

Once in Sweden I had the opportunity to test-fire the MP9 in both 9mm and 6.5mm calibres alongside other weapons for comparison purposes, in two locations; an outdoor range in semiautomatic fire and in CBJ’s indoor range on automatic. Before this, I had only been able to handle the MP9 so I was keen to see how it performed.

In either calibre the MP9 is a pleasure to shoot. I found the spacing between the butt, the pistol grip and the forward handgrip suited me well. The fat, forward-sloping front handgrip greatly aids control and I would certainly not wish to do without it. For semiautomatic fire the little 1.5x Trijicon sight proved ideal and the effective range of the 6.5mm version firing the saboted tungsten ammunition would probably be around 200 metres. In 9mm calibre or for close-range work a 1x holographic red-dot sight (also tried) might be preferred.

Given the MP9’s small size and weight I was surprised by its controllability in automatic fire. As a UK civilian my opportunities for firing automatic weapons are nearly zero but I found no trouble in keeping the rounds on target when firing short bursts; the little gun was much easier to control than an M16 I tried afterwards.

There was very little difference between firing the 9×19 and 6.5×25 versions of the MP9. Subjectively, the 6.5mm version felt as if it had slightly less recoil. My arrival coincided with CBJ’s working up of loads using their new cartridge cases. They hadn’t finalised this process and the 6.5mm version suffered some failures to feed with the new cases (although it performed very well with the older ones) but that was expected to be a temporary glitch.

A key question in my mind was this: OK, the little 4mm tungsten bullet goes through armour like the proverbial hot knife through butter, but how does it perform against unarmoured personnel? This question could only finally be decided in combat, of course, but ballistic gel provides a repeatable substitute for testing purposes. CBJ Tech has the facilities for this, and performed some tests for my benefit. I witnessed three different cartridges being compared at about 5 metres range; the standard 6.5mm saboted ball (this one first had to penetrate a CRISAT target), the full-calibre 6.5mm HET and the 9×19 NATO FMJ. The results are shown in the photograph. The least impressive was the 9mm, while the 6.5mm HET showed far more disruption with rapid bullet upset. The saboted ball also performed significantly better than the 9mm, and according to previous tests I was shown, the spoon-tip version demonstrates even faster upset as one would expect. Interestingly, on one of the test shots of the saboted rounds the sabot was found stuck into the surface of the gel block, which showed that it had followed the bullet down-range quite closely.

To sum up, the Brügger & Thomet MP9 is arguably the best of the new breed of PDWs – or machine pistols or compact SMGs if you prefer. For only about double the size and weight of a pistol (but half the size and weight of an M4 Carbine) it offers perhaps ten times the effective range plus controllable automatic fire. The use of universally-available 9×19 ammunition is proving to be an important benefit, but if more range or penetration is required the gun can easily and reversibly be converted to the impressive and versatile 6.5×25 CBJ. For any military or law enforcement organisations contemplating a weapon in this class, this could be a winning combination.

More information about the 6.5×25 ammunition is presented on the CBJ Tech website at: www.cbjtech.com.

Brügger & Thomet’s website is: www.brugger-thomet.ch/.

Anthony G Williams is an independent ammunition consultant and co-editor of Jane’s Ammunition Handbook. He maintains a website at www.quarry.nildram.co.uk

Personal Defense Weapons, or PDWs, are all the rage. Personal Defense Weapons as a genre are designed to be handy and unobtrusive to carry so as not to interfere with the military duties of combat support and combat service support troops. At the same time they are to be sufficiently lethal as to provide effective defense for the cook, driver, artilleryman, or aviator who might have dire need of an individual weapon in an emergency. While traditional handguns have inadequately filled this niche for decades, military planners have now rightfully begun to expect something more from the firearms industry. The realization that stashing a three-foot assault rifle within the confines of a truck, limousine, or helicopter is not really practical has spurred the recent expansion of several major arms manufacturers into the PDW market. The FN P-90, the H&K MP-7, and the B&T MP-9 represent but a few of these recent offerings.

It has been said that nothing in life is free and this adage applies in spades to small arms design. If you build a weapon that is lightweight and easy to carry you cannot very well expect it to stop a target wearing body armor at 1,000 meters. Lest we become too enamored with today’s whiz-bang PDW offerings, however, let us appreciate that the concept is hardly new.

The WWII-era M-1 carbine has been described in print as an early PDW. Designed to be light and handy while firing an intermediate-sized round, the fully automatic M2 version actually comes closer to meeting the criteria of an assault rifle than a PDW. While no doubt a great improvement over the M1 Garand as regards portability for second echelon troops like truck drivers and artillerymen, the carbine is still three feet long and is a bit of a nuisance to maneuver within a vehicle.

While associated with the Military Armament Corporation, Gordon Ingram and Mitch WerBell actually chased the U.S. military PDW market with some enthusiasm nearly four decades ago. Realizing that a handgun of any flavor, much less a big bore cannon like the M1911 .45, which was the service weapon of the day, was a difficult weapon with which to develop proficiency, Ingram and WerBell set out to convince the U.S. military that the MAC series of submachine guns held the most promise for arming second echelon troops for whom direct engagement with the enemy was a rare unintended consequence of their regular jobs. WerBell in particular traveled to Southeast Asia to demonstrate his weapons to military officers in a combat theater, stirring considerable interest and notoriety but few paying contracts. Given that the targets of the day did not typically wear body armor, a case could be made that they were following a doctrinally sound path.

To quote from the original Military Armament Corporation promotional sales literature for the .380 MAC-11, “The MAC/Ingram M11 is totally new and unlike any handgun ever produced. It falls loosely in the category of submachine guns…yet offers far more, in that it combines pistol mobility and an exceptionally heavy, high volume of automatic fire over reasonable, common combat ranges. Offering a sustained rate of selective semiauto or full automatic fire, the M11 successfully bridges the gap between less efficient pistols or revolvers and the limited applications of more cumbersome machine guns and submachine guns of an earlier bygone era… The vehicle driver, rear area technician, armor crewman, aviator, and crew-served weapons gunner all must have available to them a light, easily-carried automatic weapon which can produce a heavy volume of fire effective at a reasonable range.” Sound familiar? Perhaps this PDW concept is not quite so cutting edge as we might have believed.

The stubby little MAC series submachine guns were indeed handy. By the manufacturing standards of the day they were amazing. Constructed of sheet steel pressings with a minimum of machining reserved for the bolt, barrel, and fire control system, the little buzzguns could be churned out en masse for a song. Offered in 9mm, .45 ACP, and .380 calibers, the designers tried to make the MAC weapons appealing across the military and special operations spectrum.

The full sized MAC-10 in 9mm or .45 is about as compact as one might hope for in a weapon firing a general issue military cartridge. It is, however, at six pounds four ounces unloaded still uncomfortably heavy. This is, incidentally, the same weight as an unloaded, full-sized M16A1. The accelerated rate of fire necessitated by such a short bolt travel in such a tiny package makes control a challenge and effectively negates whatever training benefit a military organization might obtain over a conventional handgun.

The under-appreciated MAC-11 in .380, however, is an interesting option. Where a full size MAC-10 in 9mm tips the scales at nearly six and one half pounds and dances around rather vigorously on full auto, its .380 baby brother weighs only three and one half pounds and is fairly controllable with appropriate technique. While it does cycle at a breathtaking 1,600 rounds per minute or greater dependent upon the ammunition used, with a sound suppressor in place it is pleasant to shoot and, at reasonable ranges, acceptably accurate. If equipped with an extra six inches or so of muzzle attachment to prevent one’s shooting one’s own fingers off, the truck driver or helicopter pilot armed with a MAC-11 would be much better prepared to handle unpleasant encounters with the enemy than his counterpart armed with a conventional handgun. If the threat consists of enemy personnel bereft of body armor, a cloud of .380 projectiles is up to the task. Considering that the MAC-11 dumps its thirty-two round magazine in 1.1 seconds, from the perspective of purely Newtonian physics that’s the muzzle energy equivalent of one and one half .50 caliber BMG rounds. That’s not too shabby for a gun that weighs three and one half pounds and fits in a holster.

To quote further from the promotional literature, “With its high rate of fire and relative ease of control, it has been likened to a one-hand shotgun for its massive bursts of sheet fire… Training is greatly simplified and, as a positive adjunct, combat confidence and troop morale increase with the sure knowledge of improved hit-probability.” While the claims of near-supernatural effectiveness and ease of control might be sugarcoated somewhat, the MAC-11 did bring some interesting capabilities to the table.

The prevailing thought in the sixties and seventies was that machine pistols were interesting novelties but that they had no practical military or law enforcement applications. It was assumed that the blistering rate of fire combined with the compact platform made the military application of the fully automatic handgun more dangerous to friendly bystanders than to the enemy. The Glock model 18 has shown this to be at least somewhat presumptuous. The fully automatic Glock pistol is certainly not an appropriate issue weapon for every cop on the street or your typical Army cook but in the right hands with a little training, fire discipline, and a shoulder stock, a serious shooter can keep most of his rounds in a standard tactical silhouette at reasonable handgun ranges even at more than a thousand rounds per minute. Additionally, given that the Czech M61 Skorpion was a product of a similar era and vision and has gone on to render extensive and successful service in applications spanning both ends of the moral and legal spectrum we can see that the concept, at least at one time, had some serious merit. If nothing else, this gives us cause to rethink the practical applications of Mr. Ingram’s tiny little .380 subgun.

The MAC folding stock design has been much maligned. While extremely compact and ingeniously designed, the MAC stock requires two different manipulations for deployment and is fairly flimsy. First, the wire butt assembly must be compressed together and rotated around into its deployed position. Then the stock catch may be depressed and the stock struts extended. While the stock does wobble badly and, on the MAC-11 at least, is too short for all but the most Lilliputian of shooters, it folds up to practically nothing and provides a much more stable and effective shooting platform than one would find simply shooting the weapon off hand. This seems like one of those classic half-full/half-empty, optimist/pessimist arguments. While the wire stock on the MAC subgun is hardly in the same league with, say, the new multidimensional offering on the FN SCAR, it is still a tremendous improvement over a typical handgun sans stock and a little time on the range proves it.

On the range a serious shooter can achieve some fairly respectable performance with the little MAC. Firing semiautomatically with the stock extended placed all rounds easily within a pie plate out to fifteen meters and the 32-round magazine can keep you launching projectiles one at a time until you get bored with it. The sights are rudimentary at best but still more than adequate for the intended mission. The open bolt design does serve as a detriment to accuracy but its mass is so small that the deleterious effect is minimal. Even in the hands of inexperienced shooters, the MAC and its flimsy folding stock consistently provide better semiautomatic performance on the range than does even the most advanced tactical handgun. Taking a firm stable grip and keeping bursts between three and five rounds, a seasoned shooter can still keep a large percentage of his rounds on that same unfortunate pie plate firing fully automatically so long as a suppressor or similar muzzle attachment is employed. As a former Army helicopter pilot myself, I would much sooner sport a .380 MAC-11 with a half dozen magazines in a survival situation than an issue 9mm handgun and a fraction of the ammunition for nearly the same weight and space envelope.

One of the down sides to servicing the second echelon mission for small arms is that those troops in question are not in general “gun guys” and they do not have the luxury of extensive, regular, and repetitious training time on their individual weapons. In the case of a tiny submachine gun like the MAC-11, this is a recipe for finger amputations or worse. Considering there is not any effective mechanical impediment to allowing one’s support hand to slip out in front of the MAC-11 during recoil, the gun really is exceptionally dangerous to someone not adequately trained in its employment. Before the MAC weapons could have been safely deployed with combat troops some redesign would have been required to make it a little bit tougher to shoot one’s fingers off.

The MAC-11’s time has clearly past. Technology and history have moved on to other things and Gordon Ingram’s diminutive little submachine gun never made much of a splash outside of U.S. collectors’ circles. Were the circumstances slightly different, however, and the military leadership a bit more open-minded, some variation of a MAC series submachine gun might have found its way into the hands of sixty percent of the soldiers in the U.S. armed forces. At the very least that serves as food for thought.

The concept of a PDW (Personal Defense Weapon) is to provide personal firepower in between that of a pistol and a carbine. Several attempts have been made: the 5.7x28mm caliber by FN, the 4.6x30mm by Heckler & Koch as well as the 6x35mm by Knight’s Armament Company. The U.S. military has asked from time to time for lighter and more compact versions of the M4/M16. Colt was involved with one in particular, showed up with it and then told it was nice but they really do not have a requirement for it.

Around 1997, Colt’s Manufacturing Company, Inc. went to work on a new project. Colt was approached by Michael Harris of Special Analytical Services (SAS) with a concept of a mini-assault rifle that would have the purpose of being a personal defense weapon as well as have law enforcement and military applications. By design, the intent of the MARS was to replace the 9mm pistol as well as numerous variations of submachine guns. A Colt development team, headed by Engineer James Taylor, set out to bring Harris’ concept to life. The MARS was designed with the concept of having a smaller and lighter weapon that could win a fight against an AK47. The MARS was, and still is, different from the FN and the H&K cartridges. The 5.7×28 and 4.6x30mm cartridges primary purpose was to defeat body armor. Unfortunately after they defeat the armor, they have very poor terminal performance. They are ballistically very similar to the .22 Winchester Magnum cartridges. Harris believed the MARS could replace 80% of all pistols and submachine guns as well as up to 20% of rifles and carbines.

The 5.56x30mm Cartridge

The MARS fired a newly developed 5.56x30mm cartridge. Ballistically, the 5.56x30mm MARS cartridge is very similar to the .221 Fireball. The new cartridge was developed to enhance accuracy and range over current cartridges such as the 9mm NATO and 5.7x28mm. The MARS cartridge exploits the high energy densities of modern ball powders. The 5.56x30mm cartridge would be effective out to 300+ meters. Another goal was to enhance lethality over existing small submachine guns. The 5.56x30mm cartridge would have the penetration capabilities of the 5.7x28mm cartridge but have increased lethality over that as well as 9mm NATO ammunition. The MARS cartridge was a wildcat cartridge that was never made in quantity. All 5.56x30mm ammunition was hand loaded by Michael Harris. The cartridge began with the standard 5.56x45mm cartridge case. It was trimmed down and formed in a custom die to the proper dimensions of the 5.56x30mm cartridge. It was loaded with a 55gr full metal jacket boat tail (M193 Ball bullet), 62gr full metal jacket boat tail with penetrator core (M855/SS109 bullet) as well as a tracer bullet. Using the 55-grain bullet, the MARS rifle would fire it at a muzzle velocity of 2,620 fps out of its 10-inch barrel with muzzle energy of 838 ft/lbs. There was a problem found with the pressure levels within the 5.56x30mm MARS cartridge as the case was prone to bulge or rupture.

The MARS cartridge can be loaded to any mission specific configuration which could include hollow and soft point bullets as well as ball and armor-piercing. It is loaded up with magnum pistol-type ball propellant, which is burned at rifle pressures to achieve higher velocity in its short 10.5 inch barrel. The MARS is battlesight zeroed in at 200 meters and the path of the bullet stays within approximately 3 inches of the line of sight. The 5.56x30mm bullet will penetrate a Kevlar helmet and vest at 300 meters. The MARS was also chambered for the 9x30mm MARS cartridge which was a necked down 10mm magnum cartridge case.

There were three prototypes made during the course of development. The upper and lower receiver, bolt and stock assembly were all shortened. According to Colt’s MARS Project Manager Jim Taylor, every component was basically walked through the manufacturing process. The components nearly all started out life as standard M4 components and were modified to MARS specifications. Due to the shorter 5.56x30mm cartridge, a new magazine was created. This enabled the magazine well to be shorter contributing to the shorter upper and lower receiver. The magazine was made from a standard GI 30-round magazine. Material was removed from the middle and welded together. The follower was cut down as well. The magazine was merely a prototype and very clumsy but worked well for the testing and proof of concept.

The overall length of the collapsible stock was shorter than the standard carbine. The front portion of the stock just ahead of the locking latch was removed of an inch. Due to the shorter buffer tube a modified buffer was designed. It was similar in design to the standard buffer, just shorter. Due to the decrease in length, two tungsten weights were used and with the use of tungsten, the smaller buffer was nearly identical in weight to the standard H buffer.

The bolt carrier was shortened overall, particularly the rear behind the bolt carrier key and used a modified firing pin. The carrier key was shortened and only has one carrier key screw. The firing pin was shortened and the rear head was removed. The rear of the firing pin is visible from the top of the bolt carrier. The bolt is the standard rifle bolt assembly.

The lower receiver was modified to make it more compact and to accept the shorter magazine. The magazine well was cut in the middle, material removed and electron beam welded back together to accept the shorter magazine. This is easily seen in the prototype due to the bottom of the magazine well not being straight. The new process of electron beam welding allowed the fabrication of prototypes for a relatively modest cost. According to Colt project leader Jim Taylor, the MARS rifle may have been the first extensive use of electron beam welding for firearms prototyping. Due to the desire to maintain the bolt design and existing cam path in the bolt carrier, the MARS rifle had to modify the location of the hammer/trigger pins, selector lever and the automatic sear had to be moved slightly rearward. On the prototype MARS lower receivers, the fire control holes were drilled as per mil-spec for the M4 carbine. The original holes had to be plugged and new ones drilled in the proper location. Due to the hammer being moved rearward, a large steel roll pin was installed to prevent damage to the lower receiver if the trigger was pulled without the upper receiver installed. If the hammer was to fall on the aluminum receiver it would damage the receiver because it would hit the inside of the receiver on an angle rather than square. Due to the firing pin head being shortened, a pocket was cut into the hammer where it will strike the firing pin. This pocket allows the hammer to strike the firing pin square rather than on an angle. Also, if the disconnector was to fail, the firing pin could not protrude through the breech face to detonate the primer unless the bolt was locked. Additionally, if the hammer was to ride the bolt, there would not be sufficient energy to fire the cartridge. The MARS was designed to make use of as many existing machines and fixtures as possible to minimize the potential cost of going into production.

The upper receiver was made shorter as well. The upper receiver was cut right in front of the fired cartridge case deflector, material removed and electron beam welded back together. Additionally the ejection port dust cover was shortened. Standard handguards were used as well as the gas tube. The bayonet lug was removed from the front sight assembly. The 10-inch barrel uses the standard 1/7 inch twist and has the standard A2 compensator. The top of the barrel is stamped “MARS” to denote the caliber.

Preliminary Colt testing of the MARS indicated some highly desirable characteristics. Although relatively small, the weapon pointed like a rifle. The MARS equipped with a 1.5x optical sight firing low impulse 5.56x30mm cartridges at a relatively low cyclic rate appeared to many who fired it to be one of the easiest weapons to learn how to shoot. In hindsight, it appeared the use of the proprietary 5.56x30mm cartridge was an impediment to selling the weapon. Colt wanted to have a proprietary cartridge. Perhaps a more suitable solution would have been to go with the already currently available .221 Remington cartridge. With modern propellants, the .221 Remington cartridge may have been loaded to achieve the goals set out by Harris and Taylor for this proof of concept, and to do it without chamber pressure problems.

MARS was patented on October 27, 1998 (U.S. Patent Number 5,827,992) by Colt engineer James Taylor and Michael Harris (founder of Specialized Analytical Services). Unfortunately the MARS never found acceptance and never entered production. The main interest in the MARS was by the Israelis as a possible replacement for their police Uzi SMG. This was exactly the type of market the MARS was designed for. The production numbers that were discussed would have been 2,000 guns per year for a term of 10 years. Due to this low number of units versus the cost to tool up for the MARS, Colt decided against going into production. Colt had also felt that introducing a new compact firearm would hinder sales of their M16A2/M4 carbine variations.

I would like to thank Project Leader Mr. Jim Taylor for his assistance with this article by providing first hand knowledge of this program. I would also like to thank Colt Defense for providing access to photograph this interesting prototype weapon.

(Small Arms Review contributing editor Christopher Bartocci works as a Technical Specialist for Colt Defense LLC. The articles written by this author are of his own research and evaluation and in no way represent those of Colt Defense LLC.)

By Jim Schatz

Leaner and Meaner

While there are exceptions of course, guns and ammunition used by American military and law enforcement personnel have generally been getting smaller and lighter rather than larger and heavier during the course of the 20th century. The U.S. M4 Carbine, a lighter smaller variant of the M16A2, is now in service with many conventional military units. Compact pistols are more and more often procured for standard police uniformed issue rather than available full size handguns. The standard U.S. military service rifle cartridge has shrunk from the WWI era .30 caliber cartridge (30-06 Springfield), to the 7.62X51mm NATO (.308 Winchester) round in the early 1950’s to the current 5.56X45mm NATO cartridge commercially known as the .223 Remington. HK now offers the small 4.5 pound UMP45 submachine gun that fires the big, powerful .45 ACP slugs yet the weapon is less than half the weight of most other .45 caliber submachine guns. Even the “Ma Deuce” M2 .50 caliber heavy machine gun exists today in a lightweight high cyclic rate of fire variant. The advent of advanced lightweight materials, stronger steels and alloy metals for barrel and bolt construction, and vastly improved ammunition and bullet technology have increased the lethality and performance of today’s modern military and law enforcement firearms while at the same time lightening and lessening the load of the user.

New Start, new concept

Heckler & Koch has been working behind the scenes in their “skunk works” at their Oberndorf Germany facility on a new small Personal Defense Weapon simply called the PDW. Though primarily designed to meet current and future U.S. and European requirements for a military Personal Defense Weapon the obvious usefulness of such a weapon outside of the military becomes immediately apparent to law enforcement and special operations personnel.

To describe the new HK PDW as revolutionary as some may be tempted to do would be stretching things a bit. As a “bullet launcher” the PDW still kills by kinetic energy as small arms have been doing for centuries. It is however safe to classify this new weapon and ammunition system as a substantial development in this relatively new category of Personal Defense Weapons, a category that until recently only included the 5.7mm FN P90.

Most experts categorize a true PDW as a small easily portable weapon about the size of a machine pistol but one that shoots a non-pistol cartridge. Most PDW’s are also intended to be able to be fired using only one hand though with reduced probability of hit. Modern PDW’s are being promoted to replace handguns, pistol-caliber submachine guns and some assault rifles primarily in military support units. These personnel very seldom employ small arms in combat and when they do only for defensive purposes up close. A simple, easily portable weapon that allows for effective target engagement by lessor trained rear echelon combatants is the original role intended for the PDW. Because of the worldwide proliferation of modern hard and soft body armor today’s PDW must also penetrate protective vests and helmets in order to be effective against the aggressor underneath.

The Ammo

The HK PDW is chambered for a new proprietary cartridge developed jointly by HK and Royal Ordnance (RO), HK’s parent company and a division of BAE Systems, formally British Aerospace. RO is also the UK’s premier small arms ammunition manufacturer. The HK PDW fires a small 4.6X30mm high velocity cartridge that looks more like a small rifle cartridge than a pistol round. The overall length of the round is 1.5 inches and contains a 25-grain projectile, which reaches a muzzle velocity of 2,378 feet per second from the PDW’s 7-inch barrel. A copper-plated solid steel projectile develops @ 310 foot pounds of muzzle energy and develops recoil impulse far below that of 9mm handguns. Yet this steel core 4.6X30mm round will defeat threat (former Soviet SPETsNAZ) body armor comprised of 1.6 millimeters of titanium plating backed by 20 layers of Kevlar at ranges beyond 200 meters with sufficient residual energy to inflict lethal wounds after defeating the ballistic protection.

The “family” of 4.6X30mm ammunition currently includes eight various types of rounds many of which are still under final development. This ammo family includes a steel core military penetrator round, two types of extruded solid copper “CQB” cartridges designed specifically for use in close quarters battle were overpenetration is unwanted. One copper CQB round is being produced with a pointed tip and one with a unique “spoon nose” tip to prevent overpenetration in soft tissue or through building materials. There is also a law enforcement hollow point round that will not defeat soft body armor and dummy, blank, tracer and frangible cartridges for the weapon.

In general terms the HK PDW and its 4.6mm round are designed to provide the capabilities of a 5.56mm rifle or carbine out to ranges of just beyond 200 meters yet from a firearm that is similar in size and can actually be carried and fired like a handgun. At 100 meters the 4.6mm projectile fired from the PDW still retains more energy than a 9mm NATO ball round after perforating the threat titanium/Kevlar vest. The round will penetrate two of these former Soviet vests back to back at a range of 50 meters.

The Weapon

The HK PDW is very small indeed and resembles a large handgun. Compared to the HK .45 ACP MK23 Pistol the PDW is slightly larger though the weight of the two weapons when fully loaded (20 rounds in the PDW, 12 rounds in the MK23) is nearly identical at 2.86 pounds. For sake of comparison the PDW is 1/2 inch longer than an HK 9mm MP5K and just over two pounds lighter. With it’s optional 40 round magazine fully loaded the HK PDW weighs in at just 3.39 pounds.

Unlike all submachine guns, small assault rifles and most machine pistols the HK PDW is designed to be fired effectively with one hand at close range targets (< 25 meters). For a proficient shooter it is relatively easy to engage man-size targets using one hand at ranges out as far as 100 meters in the semi-automatic mode of fire. Accuracy is excellent. 3-inch groups at 100 meters and 8 to 12 inch groups at 200 meters from supported position employing the retractable stock for support are well within the capabilities of the HK PDW. The near absence of felt recoil, comparable to that of a lightweight .22 LR rifle, makes the HK PDW extremely controllable in full auto fire, far superior to any pistol-caliber submachine gun, insuring high hit percentages against obscured, multiple or moving targets common on the battlefield.

Specially designed shoulder rigs and thigh holsters offer the user the ability to securely carry the HK PDW on the person for instant availability. From a tactical style thigh rig the PDW can be drawn and fired like a conventional handgun in seconds. A lanyard loop in the leg rig can also be used to automatically deploy the vertical foregrip as the weapon is removed from the holster. A concealed carry shoulder rig has been developed to allow the user to carry the PDW over the uniform for hands free carry while performing other tasks. The design of the shoulder rig also allows the weapon to be presented in seconds and automatically extends the stock as it is deployed from the rig. The lightweight, small size and flat profile of the PDW when worn in the concealed shoulder rig under a light jacket will make it the weapon of choice for personal protection details in the future.

A fold-down vertical foregrip is positioned forward of the trigger guard and below the barrel. This allows the weapon to be fired using one or two hands and in conjunction with a small slide-out buttstock concealed within the polymer receiver of the weapon. The fairly central location of the pistol grip, which houses the flush mounted 20-round magazine, allows for practical use as a one handed gun. Unlike many pistol-caliber machine pistols such as the HK MP5K the new HK PDW offers greater control and probability of hit due to the 4.6mm rounds minimal felt recoil and long eye relief reflex sight.

The HK PDW is gas operated employing a unique clean shooting system similar to that used with great success in the HK G36 weapons system. A multi-lug rotating bolt head that interlocks with the barrel provides for a secure seal of the breech during firing. All operating controls of the PDW are fully ambidextrous to include the magazine and buttstock releases, the M16-like cocking handle and centrally mounted safety/selector lever. Current prototypes of the HK PDW provide both semi-automatic and fully automatic modes of fire at a theoretical rate @ 700 rounds per minute.

The HK Personal Defense Weapon also possesses a combined forward assist/bolt catch and bolt release lever, sling mounting points and an integral Picatinny sight-mounting rail. Back-up emergency iron sights are incorporated into the design as well. The weapon is produced predominately from lightweight polymers with metal used only where absolutely required. The simple design, minimum number of parts and polymer construction translates to very little user maintenance due in great part to its unique short stroke gas operating system. Barrels are removable with a simple wrench and are thus user replaceable. A threaded barrel is available as an option for the attachment of optional flash hiders, sound suppressors or other muzzle mounted accessories.

The Hensoldt PDW Reflex Sight

The sighting system for the PDW, like the weapon and ammunition family are still in the final stages of development. Developed specifically for the Heckler & Koch PDW by Hensoldt, a division of Zeiss, the small PDW Reflex Sight uses a collector to capture ambient light and illuminate a small gold aiming dot. This dot can be seen with both eyes open whether the weapon is fired at arms length like a pistol or when shot from the shoulder using the buttstock for additional support. The sight includes an optional tritium source or battery back up to power the dot during periods of low or no light. A pair of simple recessed Allen head screws allows for internal windage and elevation adjustments of the 7.5 moa dot.

Like everything else about the HK PDW and 4.6mm ammunition, this unique PDW sight is designed to be lightweight, portable and durable under the harshest environmental conditions. For use with the PDW, HK designed their own simple rail grabber sight base that can be used to attach the Hensoldt sight to any Weaver or Picatinny (MIL-STD-1913) accessory rail in under a second and without tools or hardware of any kind. The presence of the Picatinny mounting rail on the top of the PDW will allow a wide range of sights to be attached using currently available rail grabbers.

Operational Uses abound

With a maximum effective range of greater than 200 meters the small size of the weapon, similar to a large handgun, will allow it to be used effectively for VIP protection where the weapon must be concealed yet readily available. Its ability to defeat threat body armor and vehicle windshields and body panels would make it perfect for facilities defense where overpenetration and maximum range of a rifle in urban areas might be of concern. Certainly in a classic role as a PDW for military pilots, drivers, artillery and armor crewman, medics, communication specialists, members of crew served or anti-tank weapons crews, forward observers and behind the front line support personnel the HK PDW will be far better than a handgun from a terminal performance and hit probability standpoint. The 2.86-pound HK PDW promises to be far more portable and manageable than a rifle, carbine or smg, especially in confined spaces like vehicles, aircraft and within mobile communications trailers. The author has worn the PDW in the leg rig while running, climbing and driving. It is a weapon that does indeed “wear” comfortably like a pistol yet hits like a rifle at a distance of more than two football fields.

Current Status

Prototypes of the Heckler & Koch PDW have been undergoing testing for more than four years and to date have seen limited exposure in the United States. At this point the PDW is being shown to select prospective users for design input and comment. HK PDW’s are not yet available for customer demonstrations. Availability of production weapons is not expected before mid-2001. The 4.6mm ammunition is already in limited series production and available from the Royal Ordnance Radway Green factory in England to support the continued development and early user evaluation of the weapon. HK is negotiating with several U.S. ammunition companies to have the ammunition produced in America as well as in the U.K. Projected ammunition unit cost is expected to be very affordable, less than 9mm ball ammunition, and all rounds will be non-toxic to meet growing concerns in this area.

Certainly this new Heckler & Koch Personal Defense Weapon marks a serious attempt to provide the true performance required of a personal weapon and in a small package that can be easily carried and thus always available. If during the remaining testing the weapon and new cartridge perform as expected the HK Personal Defense Weapon could be the future choice for an entire spectrum of users.

About the author: In addition to being a regular contributing writer for this magazine, Jim Schatz is also a full-time employee of Heckler & Koch, Inc. Since 1986 Jim has served with HK in the roles as a training instructor and customer service, sales and product developer for HK’s Federal Operations Department serving all U.S. federal law enforcement and military organizations. The information and opinions provided herein are those of the author and not HK.

During a recent small arms symposium in the UK in September Heckler & Koch released information on a new Personal Defense Weapon for the first time publicly.  Rumored for some time to be in development at HK’s “skunk works” in Oberndorf Germany, the existence of what some are calling a revolutionary weapon has been confirmed.

Little detailed information is available at this time and few photo’s. the new HK PDW is yet another totally new weapon from HK at a time when few other firearms companies are developing much of anything new. The PDW joins the ever increasing list of new HK’s along with the G36 and SL8-1 rifles, .45 and .40 caliber UMP submachine guns and various new pistol models like the USP Expert and a new centerfire .46 ACP carbine called the USC shown at the 1999 SHOT Show and expected to be available on the U.S. market later this year.

To describe the PDW as revolutionary as some may do may be stretching things a bit. As a bullet launcher this new PDW still kills by kinetic energy as firearms have been doing for centuries. Certainly this new personal weapon can be classified as a substantial development in this relatively new category of Personal Defense Weapons, small easily portable weapons about the size of a machine pistol or small submachine gun but a weapon shooting a non-pistol cartridge.

What is known about the HK PDW is that it is chambered for a new proprietary cartridge developed jointly by HK and Royal Ordnance, HK’s parent company and the UK’s premier small arms ammunition manufacturer. The PDW fires a small 4.6mm high velocity cartridge that looks more like a small rifle cartridge than that of a pistol round. The overall length of the round is 1.5 inches and contains a 25-grain projectile with a reported muzzle velocity of 2,378 feet per second. A copper-plated solid steel projectile develops @ 310 foot pounds of muzzle energy and is said to develop recoil far below that of 9mm handguns. According to the HK briefing presented in England the 4.6X30mm round will defeat threat body armor comprised of 1.6 millimeters of titanium and 20 layers of Kevlar at ranges beyond 200 meters with sufficient energy to inflict serious wounds after defeating the ballistic protection. Various types of rounds are under development to include a ball round, steel core penetrator round and a machined copper “CQB” cartridge for use in close quarters battle were over-penetration is unwanted. A tracer and frangible round for the PDW are also being finalized.

Actual firing prototypes of the PDW exist and have been appearing at the more recent U.S. defense expositions where the accompanying photographs were taken. Availability of production weapons is said to be scheduled for late 2,000 and ammunition is already in production and available from the Royal Ordnance factory in England. The weapon is very small indeed and resembles a large handgun. A briefing slide in fact compared the new HK PDW with the HK .45 ACP MK23 Pistol and while certainly larger the weight of the two weapons when fully loaded (20 rounds in the PDW, 12 rounds in the MK23) is nearly identical at 2.86 pounds. For sake of comparison the PDW is 1/2 inch longer than the HK 9mm MP5K without buttstock and just over two pounds lighter.

According to HK the PDW is designed to be fired effectively with one hand unlike the much larger and heavier FN P90 submachine gun, once referred to as a Personal Defense Weapon. The FN 5.7mm family of weapons that include the P90 and Five Seven pistol is clearly HK’s primary competitor in this relatively new weapons category. With its optional 40 round magazine fully loaded the HK PDW weighs in at 3.39 pounds compared with the P90 with 50 rounds loaded at over 7 pounds. The HK PDW is more than 6 inches shorter in length than the P90 as well making it far more portable as a true PDW must be.

According to HK’s data the 4.6mm round fired from the PDW provides the capabilities of a 5.56mm rifle or carbine out to ranges of just beyond 200 meters yet from a firearm that can actually be carried like a pistol. (SAR has not yet seen the gelatin tests or ballistics on this round) Shoulder rigs and thigh holsters offering quick deployment like that of a handgun holster are rumored to be under development by HK for their PDW. This looks like a head to head battle brewing between HK and FN in a weapons category that has yet to be embraced by many potential users but is slowly taking shape as future potential defensive armament for personal protection of military and law enforcement personnel.

What we know of the weapon is very interesting. A fold-down vertical foregrip is positioned forward of the trigger guard and below the barrel. This allows the weapon to be fired using one or two hands and in conjunction with a small slide-out buttstock concealed within the polymer receiver of the weapon. The fairly central location of the pistol grip, which houses the flush mounted 20-round magazine, allows for practical use as a one handed gun unlike most machine pistols.

The HK PDW is gas operated employing a clean shooting system rumored to be similar to that used so successfully in the HK G36 weapons system. A multi-lug rotating bolt head provides for a secure seal of the breech during firing. All operating controls of the PDW are fully ambidextrous to include the magazine and buttstock releases, the M16- like cocking handle and safety lever. The PDW provides the user with both semi-automatic and fully automatic modes of fire at a theoretical rate of @950 rounds per minute.

The HK Personal Defense Weapon provides the user with a forward assist, sling mounting positions and an integral Picatinny sight-mounting rail. The weapon is produced predominately from lightweight polymers and steel only when required. The PDW is said to require very little maintenance due to its unique short stroke gas operating system.

The sighting system for the PDW like the weapon itself is said to be still in the development stages. The sight pictured herein is being developed for Heckler & Koch by Hensoldt, a division of Zeiss, and like the dual sight on the HK G36 rifle uses a collector to capture ambient light and illuminate a small red aiming dot. This dot can be seen with both eyes open whether the weapon is fired at arms length like a pistol or when shot from the shoulder using the buttstock for additional support. A tritium source within the sight or a battery recharged by the solar collector is being considered to power the dot during periods of low or no light. This extremely small sight, like everything else about the HK PDW and 4.6mm ammunition, is designed for lightweight and portability. HK even designed their own simple rail grabber sight base for the PDW sight. The presence of the Picatinny mounting rail will allow a wide range of sights to be attached to the PDW using currently available rail grabbers. A fixed from sight pot is provided on the weapon as is an adjustable rear Patridge style sight.

Certainly this new Heckler & Koch Personal Defense Weapon marks a serious attempt to provide the true performance required of a personal weapon and in a package that can be easily carried and thus always available. If the weapon and new cartridge perform as claimed this new weapon could be the future choice of all categories of users. With a maximum effective range said to be somewhere between 200 and 300 meters the size of the weapon will allow it to be used effectively for VIP protection where the weapon must be concealed yet readily available It’s ability to defeat threat body armor and vehicle windshields and body panels would make it perfect for facilities defense where over-penetration and maximum range in urban areas might be of concern. Certainly in a classic role as a PDW for military pistols, drivers, artillery and armor crewman and behind the front line support personnel the PDW would be far better than a handgun and more portable and manageable than a rifle, carbine or smg, especially in confined spaces like vehicles, aircraft and within mobile communications trailers.

SAR will provide more detailed information on this newly emerging HK gun, as it becomes available.