by Al Paulson

Sound Technology’s integrally suppressed Ruger Mark II pistols have a long-standing reputation for excellent sound suppression, long service life, and exceptional accuracy. For example, one long-range fanatic I know mounted a 48-power rifle target scope on a Sound Tech suppressed KMK-10 pistol and shoots quarter-sized groups from a sandbag rest on a calm day at 200 yards using Ely TENEX ammunition. An animal-control professional who buys five integrally suppressed Sound Tech pistols a year finds that the Ruger Mark II pistol wears out before the Sound Tech suppressor (after approximately 200,000 rounds). This study provides a brief but detailed look at the performance of Sound Tech’s most popular silenced .22 pistols at the time of this writing – a combination of target, sporting, and pocket pistols featuring either integral suppressors or muzzle cans.

Integrally Suppressed Ruger Mark II Pistols

The flagship of the Sound Tech line is Mark White’s Model M integrally suppressed Ruger Mark II, which is typically based upon KMK-512 (stainless) model pistol. Those who would prefer a blued pistol usually have theirs built on a P-512 (the Ruger 22/45 with 5.5-inch blued bull barrel), that is 7 ounces lighter and about $50 cheaper than the KMK-512. Before I graduated to progressive multifocal eyeglasses, my pick of the litter was the variant evaluated in this study, which features a 1×9.5-inch suppressor tube. Now I prefer the Sound Tech variant with 1×8-inch tube, which is easier to shoot with progressive multifocals. While most of Sound Tech’s clients also prefer the 8-inch model, it is the longer suppressed variant that is truly the flagship of the Sound Tech line, so the 9.5-inch model is the subject of this study.

The suppressed pistol with 9.5-inch tube looks like an unmodified KMK-10 pistol, since the suppressor tube blends gracefully with the receiver and the muzzle cap is TIG-welded, ground, sanded, and carefully polished so there is virtually no evidence of a separate end cap seam nor are there assembly wrench holes to give the game away. From both visually stealthy and aesthetic points of view, this is a snazzy presentation.

How much bulk and weight does an integral suppressor add to an unmodified pistol? The KMK-512 features a 5.5-inch bull barrel, with an overall length of 9.75-inches and a weight of 42.0 ounces. The KMK-10 features a 10-inch bull barrel, with an overall length of 14-5/16 inches and a weight of 51 ounces. Sound Tech’s integrally suppressed pistols feature a barrel placed under tons of pressure to minimize barrel harmonics and maximize accuracy, special porting 3 inches from the breech – not to maximize sound suppression, but rather to maximize accuracy, and a baffle design that does not accumulate gunk as rapidly as some other designs. The variant with Model M suppressor with 9.5-inch tube is 15.0 inches in overall length, and it weighed 48 ounces new. That’s 6 ounces heavier than an unmodified KMK-512. Compared to an unmodified KMK-10, a new Model M with 9.5-inch tube is 3 ounces lighter and 11/16-inch longer. While the weight is quite manageable, the 9.5-inch tube is a lot of architecture to manage. Therefore, I’d recommend fitting the pistol with Hogue rubber grips with thumb rest to make the pistol a lot more comfortable to hold and fire.

I should note that after more than 50,000+ rounds have been fired though it, this pistol has gained an additional 0.7 ounce of accumulated lead that has plated the inside of the suppressor. (Loose lead dust can be shaken or flushed out, and disposed in an environmentally responsible manner.) The pistol is still a tack-driver, and it still provides excellent sound reduction, as Table 2 shows.

This accumulation of lead has implications for the safety of indoor ranges as suggested by unpublished Finnish academic research reported in Paulson (1996). Finnish research suggests several things about the risk of lead poisoning at indoor ranges. (1) Friction with the rifling in the bore and possibly interaction of hot combustion gases with the exposed lead at the rear of a lead bullet turn some lead into a vapor. (2) The lead vapor condenses into fine lead dust after it has left the muzzle. Airborne vapor and dust can be inhaled directly. This fine lead powder quickly settles on flat environmental surfaces. (3) If disturbed, the lead dust can be inhaled. (4) Inhaled lead vapor and dust will slowly poison the shooter. Lead poisoning – like radiation poisoning – is cumulative.

The Finns postulated that the lead vapor condenses out inside the suppressor as lead dust and that it also plates the internals and previously accumulated lead, if present. Since Mark White caters to animal-control professionals whose employees may shoot 100,000 rounds per year out of a suppressed .22 LR pistol, he’s had the opportunity to dissect his own and other integrally suppressed .22 Rugers after they’ve been retired. These dissections confirm the Finns’ contention that a significant amount of lead vapor is trapped inside a suppressor, thereby reducing the amount of lead vapor and dust discharged into the environment.

White’s S-baffle design is good at redirecting hot combustion gases into places inside the suppressor, where it condenses out and remains inside portions of the suppressor, where the accumulated lead has minimal effect on sound reduction, accuracy, or operational lifespan.

Furthermore, in a truly objective world, there is an argument to be made that the US Environmental Protection Agency should offer government grants to agencies, companies, and individuals with indoor shooting ranges for the purchase of sound suppressors both to reduce the risk of hearing damage, and to reduce the risk of heavy-metal poisoning from inhaled lead vapor and dust.

Sound Tech packs a lot of technology into a net gain of 6 ounces over the KMK-512. As White points out, “There are two ways to suppress the Ruger Mark II: integral suppressors and muzzle cans. The integral suppressors seem much simpler from the outside, but they are much more complex inside compared to muzzle cans. Integrally suppressed pistols are attractive because they have graceful lines and are capable of extraordinary accuracy if carefully designed and built. But there is no free lunch, as one writer says from time to time.

“From the end-user’s point of view, integrally suppressed pistols deliver less projectile velocity than a pistol with a muzzle can. This can be a good thing or a bad thing, depending upon which ammunition is used and the needs of the operator. Another negative with integrally suppressed Ruger pistols is that they need much more frequent cleaning than pistols using muzzle cans.”

“A good thing about integrally suppressed Ruger Mark IIs,” White continued, “is that integral suppressors are much more robust than pistols fitted with muzzle cans. The threaded interface between a muzzle can and a handgun is the weakest link in the system. A very hard blow to the front of the muzzle suppressor can bend the mount and cause misalignment of the baffles with the pistol’s bore.

“From the manufacturer’s perspective, integrally suppressed pistols are so much more expensive to build that most makers of premium suppressed pistols barely break even. Integrally suppressed Mark IIs are flagships of the designer’s art, not sources of income. Still, whether you are an end-user or a manufacturer, you gotta love ‘em. As someone once said, ‘Few firearms exhibit such a graceful marriage of form and function as the integrally silenced Ruger Mark II.’”

While Mark White and I prefer the visually stealthy integrally-silenced models just described, some collectors want their integrally-suppressed pistol to look like a gnarly silenced weapon rather than a nifty but otherwise unremarkable, unmodified target pistol. For these folks, White designed a “bulldog” variant of the silenced KM-512 with 1-3/8 by 6-3/4-inch tube that shouts, “silenced pistol!” to anyone who sees it. Called the M2 Model, the beefy bulldog variant evaluated in this study has an overall length of 12-3/8-inches and a weight of 47.2 ounces.

Performance of Sound Technology’s Model M with 1×9.5-inch tube and Model M2 with 1.38×9.5-inch integrally suppressed Ruger Mark IIs were tested with three kinds of Remington .22 Long Rifle ammunition: 40-grain RN high velocity (HV), 40-grain RN standard velocity, and 38-grain HP subsonic. Suppressed performance was compared to an unsuppressed Ruger KMK-512. All pistol and suppressor combinations were tested on the same day at temperatures raging from 52 to 54 degrees Fahrenheit. The speed of sound varied from 1,109 to 1,111 fps. An earlier test on the Model M suppressed pistol was conducted at 80 degrees, when the speed of sound was 1,139 fps. This study employed the testing regimen and equipment used by Paulson (1996) as amended by Paulson, Parker, and Kokalis (2002). Suppressed and unsuppressed sound pressure levels appear in Table 1. Net sound reductions appear in Table 2, and muzzle velocities appear in Table 3.

I had the opportunity to test the same Model M with 1×9.5-inch suppressor when it was relatively new (after 8,000+ rounds had been fired through it), and again more than four years later after 50,000+ rounds had been fired through it. I use the phrase “fairly new” with a hint of irony, since nice integrally suppressed pistols that I’ve studied over the years have demonstrated life spans varying from 10,000 rounds to 200,000 rounds. At the low end of that range, lead buildup resulting from poorly designed or executed barrel porting – frequently exacerbated by the design of structures immediately downstream of that porting – has been responsible for the low-end life spans.

As seen from the first batch of data listed in Table 1, the relatively new M2 system delivered mean (average) sound signatures of 114, 109 and 110 decibels with high velocity, standard velocity and subsonic ammunition, respectively. Compared to action noise of 109 decibels (measured as the sound of the bolt closing on an empty chamber, using the bolt-release lever), this is stellar performance. Sound Technology’s Model M integrally suppressed pistol is most accurate with standard velocity ammunition, and the sound signature equals the action noise with this ammunition. What more could you want?

Testing after another 42,000+ rounds had been fired through this system produced the second batch of Model M data in Table 1. These data show that the muzzle blast of the integrally suppressed pistol is within 3 dB of action noise with subsonic ammunition. Remember, this pistol already had 50,000+ rounds through it before this second batch of tests was conducted.

It is interesting that the larger diameter M2 1.38×6.75-inch bulldog variant was not as quiet as the Model M 1×9.5-inch flagship variant despite the fact that they have nearly identical volumes (9.3 versus 9.5 cubic inches, respectively). This confirms the old suppressor design rule of thumb that, “Given two suppressors of equal volume, the longer one (typically with more baffles) will be the quieter one.” This old theorem dates back to the days of simple symmetric baffles. Another factor is at work here, since White uses relatively few baffles. Sound Tech’s S-baffles are uniquely asymmetric, and they work more efficiently with higher gas pressures. Therefore, decreasing tube diameter actually improves their efficiency. If you absolutely lust after a gnarly, integrally suppressed Ruger Mark II that provides good sound suppression and outstanding accuracy, then Sound Tech’s Model M2 provides .177-caliber pellet-gun-level sound signatures with standard velocity and subsonic ammunition, and quite usable stealthiness with high velocity fodder.

For my own biases, however, I’d much prefer the graceful lines and stellar performance of Sound Tech’s Model M integrally silenced Mark II pistol.

Taking Stock

One of Sound Technology’s customers came up with a removable, non-attached buttstock that is 7 inches long and greatly extends the effective range of a suppressed Mark II pistol. He has graciously allowed Mark White to manufacture the stock for Sound Technology customers. The front of the stock features a channel that cups the rear of the pistol grip and is held in place by the thumb of the strong hand. The factory adjustable notch-type rear sight works remarkably well so close to the eye, but Brownell’s carries a replacement peep sight that works much better. This makes a dandy accessory for my suppressed kit gun. Two variants of the stock are available: bright stainless steel to match bright stainless suppressed pistols, and a chrome moly steel version finished in black powdercoat to match matte black suppressed pistols. The stainless stock weighs 10 ounces. I find it a most useful accessory in my survival kit, when kayaking or otherwise traveling in wild places.

Stalking the Stealthy Walther P-22

The appearance of the Walther P-22 has been nothing short of a sensation. The diminutive sibling of the 9x19mm Walther P-99, this compact .22 LR pistol retains its bigger brother’s manners and comportment. Two variants are available: one with a 3.5-inch barrel and one with a 5.0-inch barrel. The shorter P-22 is generally preferred for adding a sound suppressor, since it will keep all ammunition subsonic, even with the freebore boost typically generated by a sound suppressor (see Table 3). The remarkably thin barrel is held in tension by a barrel bushing, which is normally replaced by a threaded bushing when a sound suppressor is to be fitted.

Sound Technology’s Squelch sound suppressor is unusual in that its rear mount replaces the factory barrel bushing. No additional adapter is required. Not only is this a cheaper solution, it minimizes the risk of suppressor misalignment of the bore. “A Walther P-22 barrel adapter,” Mark White observed, “has two alignment surfaces and two sets of threads, each of which offers a chance for misalignment. Incorporating the adapter into the silencer is simpler, stronger, and less prone to problems.” To shoot the P-22 without the suppressor, simply unscrew the silencer and re-install the factory barrel bushing.

The Squelch model sound suppressor from Sound Technology comes in two basic variants. Both are fabricated from chrome moly steel and are finished in a nonreflective black powdercoat. The basic or standard Squelch measures (S-Can for short) has a diameter of 1.128 inches, a tube length of 5 inches, and a weight of about 8.7 ounces. The Super Squelch suppressor has a diameter of 1.38 inches, a tube length of 5 inches, and a weight of about 10 ounces. The bigger suppressor is quieter, but the smaller suppressor is more aesthetically pleasing. The smaller Squelch model was used for this evaluation of the Walther P-22. The Squelch siblings are designed as dry cans; the sound signatures and net sound reductions reported in Tables 1 and 2 were obtained with a dry can. That said, one could virtually eliminate first-round pop and lower the noise of subsequent shots by putting a small amount of red Jet Lube or a short squirt of WD-40 in the rear expansion chamber before making the cold shot of the day.

Tables 1 and 2 show excellent sound reduction for a dry muzzle can on a short-barreled pistol. The Squelch delivered 36-, 38-, and 39-decibel sound reductions with Remington high velocity, standard velocity, and subsonic ammunition, respectively. This is wet can performance out of a dry can. It is safe to say this is an impressive achievement. Furthermore, dry cans are a whole lot more fun to shoot than wet cans.

Contrary to some reports on the Internet about finicky reliability based upon ammunition type, this suppressed P-22 cycled with absolute reliability using all kinds of ammunition, keeping offhand hits in pop can bottoms during rapid-action drills. The increased backpressure generated by the sound suppressor may have contributed to this enhanced reliability.

Sound Technology’s Squelch silencer on the Walther P-22 with 3.5-inch barrel is a fun, sensual, stealthy combination.

Silencing the Beretta 21A Pocket Pistol

The 12.3-ounce Beretta Model 21A seems to be the most robust and reliable .22 LR pocket pistol suitable for suppressing. The Mossad (Israel’s CIA) and Israel’s sky marshals have used a longer-barreled version of the Model 21A for decades as their primary duty weapon, due to the round’s sound and penetration characteristics, as well as the ability to hide the tiny weapon in deep concealment.

Such short-barreled pistols as the Model 21A produce a much louder report and belch more carbon monoxide and unburned particulates in the flash than pistols with longer barrels (see Table 1). Sound Tech’s Squelch can for the Beretta is specially designed to work with this particular pistol once it has been fitted with an aftermarket barrel threaded 1/2×28 TPI. The beefy Beretta Squelch weighs 15.5 ounces, compared to the Model 21A’s weight of 12.6 ounces with threaded barrel. The Beretta Squelch has a tube length of 5.25 inches, an overall length of 5.38 inches, and a business-like girth of 1.128 inches. The Beretta Squelch drops the weapon’s gunshot noise down to airgun levels; the Crossman American Classic Model 1377 .177 caliber air pistol, for example, delivers a sound pressure level of 120-123 dB, depending upon the number of pumps. The Beretta Squelch provides excellent performance in a dry can when mounted on a 2.4 inch barrel.

So there it is, the Sound Tech .22 Pistol Sampler. There’s a terrific treat for nearly any taste. The only problem is that it’s hard to pick just one.

Literature Cited

Paulson, A.C. 1996. Silencer history and performance. Volume 1. Sporting and tactical silencers. Paladin Press, Boulder, CO. 424 pp.

Paulson, A.C, N.R. Parker, and P.G. Kokalis. 1996. Silencer history and performance. Volume 2. CQB, assault rifle, and sniper technology. Paladin Press, Boulder, CO. 429 pp.

Sources:

Sound Technology
Dept. SAR
P.O. Box 391
Pelham, AL 35124
Phone and fax 205-664-5860
Website: http://www.soundtechsilencers.com

By Al Paulson

Few firearms exhibit such a graceful marriage of form and function as the integrally silenced Ruger Mark II. The Ruger is both accurate and durable, as well as handsome. Yet one does hear a few gripes from time to time about how quickly the Ruger action gunks up with powder residue, how difficult the action is to clean and reassemble after field stripping, and how heavy the suppressed Ruger is both for extended carry as well as for kids, and wives, and first-time shooters. Some folks are simply bored with the Ruger and want something different. Unfortunately, few accurate, robust, and practical-to-suppressed alternative pistols have appeared over the years. Therefore, integrally suppressed Ruger pistols have dominated the suppressed .22 pistol marketplace since the Vietnam era. An attractive and viable alternative to the Ruger appeared in 1999 with the introduction of the Camper model of the Browning Buck Mark.

Unlike the Ruger, which has an ejection port on the right side of the receiver, the Browning has an open receiver when the slide recoils back during the action sequence. This enables the back pressure of combustion gases to blast unburned powder residue out both sides of the action, keeping it much cleaner than a Ruger action after firing the same number of rounds. While the suppressed Ruger action needs to be cleaned every 500 rounds, the suppressed Browning action only needs cleaning every 1,500 rounds. That’s a big plus for many sport shooters and animal-control professionals.

The Browning Buck Mark Camper is also lighter than a comparable Ruger. With a bull barrel length of 5.5 inches and an overall length of 9.5 inches, the Browning Camper weighs 34 ounces. A Ruger KMK-512 with 5.5-inch bull barrel has an overall length of 9.75 inches and weighs 42 ounces. It is the KMK-512 model that is commonly used for high-end integrally suppressed Ruger pistols, such as AAC’s Phoenix pistol. The Browning Camper is also about $160 less expensive than the Ruger KMK-512. Other noteworthy features of the Browning Camper include molded rubber grips, a top strap above the slide for mounting the a fully adjustable rear sight (which does not move back and forth with the slide), and an unusually nice factory trigger nominally set for 3.5 pounds. The test specimen used in this study started out with a trigger pull of 4.1 pounds when factory fresh. Pull dropped to 3.7 pounds after the first 200 rounds had been fired.

The Dragonfly from the Advanced Armament Corp. represents an attempt to marry the lightest possible suppressor to the Buck Mark Camper pistol to capitalize on the light weight of the Browning handgun. The Dragonfly suppressor is fabricated from 6061-T6 aluminum and 304 stainless steel. (The Buck Mark frame is machined from a block of 7075-T6 aluminum.) The suppressor tube is 7.25 inches long and 1.0-inch in diameter, and is finished in a matte black anodizing. The barrel is turned down to save weight, and it is placed under tons of tension to minimize barrel harmonics and drift from heating, thereby maximizing accuracy. The suppressed Browning Camper pistol has an overall length of 13.5 inches and a weight of 30 ounces with an empty magazine. Thus the Dragonfly is 2.2 inches longer and yet 4 ounces lighter than the unmodified Browning Camper pistol. The light weight and longer sight radius, plus the fact that this is a silenced pistol, mean that the Dragonfly will be particularly kind to new shooters and shooters of small stature like kids.

These same characteristics make this an ideal firearm for training individuals in beginning pistol safety and marksmanship. As an NRA instructor, I’ve used silenced pistols for teaching since the 1980s. It is much easier to teach and to maintain safe gun handling practices when students are not encumbered by shooting muffs or plugs. It is also worth noting that shooting muffs frequently do not seal well on the smaller heads of young people, and plugs may be painfully large in the smaller ear canals of the young. This problem is made more serious by the fact that the young are more susceptible to hearing loss from gunshot noise. A pretty good shooting muff that will still allow a cheek weld on a long arm, such as the Peltor Bullseye 9 model, drops noise by 22 decibels. That assumes that the muff obtains a perfect seal on the head, which may be problematic with small-statured individuals. Peltor recognized this problem and introduced a Junior model, which only drops noise by 17 dB, but at least it’s much more likely to seal properly on a youngster. Peltor is certainly to be commended for introducing a muff for youth and small adults. Clearly, any sound suppressor that produces more than 17-22 dB sound reduction (kid versus adult muffs) will not only give better hearing protection than the shooting muffs, it will also provide a much better environment for teaching basic shooting fundamentals and fostering safe gun handling on the range or at the family picnic.

Then there is the matter of aesthetics. Are you bored with the looks of silenced Ruger pistols? Browning offered a special run of Camper frame colors in red, green and blue for the most exuberant tastes, as well as black for stodgy traditionalists like myself. AAC stocks Dragonflies in all of those Browning frame colors.

By way of comparison to the Dragonfly, AAC’s integrally silenced Ruger Mark II, called the Phoenix, has a 7.5-inch stainless steel suppressor tube and weighs 42.5 ounces with empty magazine. That’s only 1.1 ounces heavier than an unmodified KMK-512 pistol. While that’s relatively light as suppressed Ruger pistols go, it’s still 12.5 ounces heavier than the suppressed Dragonfly.

In the history U.S. folklore and firearms development, the story of the late Bill Ruger’s Mark I and Mark II pistols are probably as well known as the chapter on Sam Colt’s .45 caliber Peacemaker. Most folks are not particularly well versed on the origins of the Browning Buck Mark series, however, so a very brief history is in order before we conduct a hands-on evaluation of AAC’s Dragonfly. Advanced Armament’s suppressed Browning was tested against AAC’s suppressed Ruger (a Phoenix), which was used as a frame of reference.

Buck Mark Origins

In the beginning… (which in this case means anno franca 1914), John Moses Browning created the Colt .22 Automatic Target Pistol. And it was good.

In fact, it was dandy. Colt began production on March 29, 1915. Browning’s pistol featured a rather unusual innovation. A slide ran along the top of the receiver for the rear half of its length, and it separated completely from the breech end of the barrel upon firing. Combustion gases pushing on the spent case drove the slide rearward from the fixed barrel to power the extraction/ejection sequence of this simple blowback design.

The magazine was redesigned to accept high-speed ammunition about 1920, and the pistol was subsequently renamed the Colt Woodsman in 1927 (Browning and Gentry, 1964, 1994). Various target and sporting models were introduced and in the 1930s, but were discontinued in 1940 with the appearance of war clouds on the horizon. Two post-war Woodsman variants appeared in 1947 (a sporting and a target model). An economy model was introduced as the Challenger, which was renamed the Huntsman in 1955. Colt production ended in January 1963 with a total production of 539,232 Woodman pistols of all models.

If imitation is the highest form of flattery, then the original Woodsman was indeed a praiseworthy design, judging by how many times the Woodsman’s basic blowback design principles and overall aesthetics have been copied over the intervening nine decades. Fabrique Nationale d’Armes de Guerre of Belgium produced many Browning designs under license for the Browning branch of FN’s product line. John M. Browning began his relationship with FN by signing a contract on July 17, 1897 for exclusive world rights to manufacture and sell his .32 caliber self-loading pistol, which was marketed as the Browning Model 1900.

A half-century after its introduction by Colt, grandson Bruce Browning redesigned the Woodsman for Fabrique Nationale to take advantage of new processes and materials to streamline manufacturing and reduce production costs. Here’s where the story gets a bit hard to follow, depending upon which historian you read. Part of the problem is that model names appear to overlap different actual designs, and more recent work that came to hand does not cover all the important basic models I’ve seen myself.

W.H.B. Smith (1966) says that Browning simultaneously introduced three improved pistols based upon the earlier Woodsman design in December 1961, but commercial production did not actually begin until 1962. All three of the new pistols featured non-recoiling sights, open sides but a covered top of the receiver, and a barrel that could be removed by loosening a slotted screw with a coin. The Browning Medalist was a high-end target pistol with many advanced features, and the Challenger was a more affordable target pistol without the ventilated rib, thumb-rest stocks, wood fore end, or other bells and whistles of the Medalist. Both featured a steel frame, slide hold-open latch, adjustable trigger, and checkered walnut stocks. The Nomad, according to Smith, featured an aluminum frame to reduce weight and-more importantly-to reduce production costs. The Nomad had plastic stocks, an open rear half of the receiver like the modern Buck Mark, and neither an adjustable trigger nor slide hold-open latch. This economy model of the Browning line featured an aluminum frame from its introduction until 1966, when a steel frame was introduced for the Nomad.

As has been the trend of all firearms designs of old world lineage, eventually even the new Nomad econo-pistol itself became too expensive to manufacture. According to one recently published history of the Browning Buck Mark: Lee Farber, the owner of Arms Technology, Inc. (ATI) in Salt Lake City, redesigned the Nomad. That’s not really true. Browning’s own Joe Badali redesigned the pistol and Farber “industrialized” it. This means Farber performed the critical task of making Badali’s new design efficient and economical to produce, by using such gambits as using investment castings of the slide and other small components to reduce costs. Fielding an excellent product depends upon both a gifted designer and a gifted industrializer. These are rarely overlapping skills. This descendant of the Woodsman reached the marketplace in 1976 as the Challenger II (not to be confused with the 1960s-vintage Challenger, now referred to the Challenger I). The Challenger II featured a sporter-weight barrel, an open slide at the back, and a steel frame.

After further redesign of the pistol and magazine by Joe Badali, the Challenger III pistol appeared in 1982. It featured an aluminum frame and a target-weight barrel. Next Badali incorporated the latest advances in both manufacturing technology and metallurgy into the Challenger III, producing the latest Woodsman descendant—the Buck Mark, which first appeared in 1985.

It is safe to say that the Buck Mark represented a big improvement over the evolving Challenger series, and it also brought the fabrication of Browning .22 pistols back to the States from Belgium. Buck Marks are manufactured for the Browning Arms Company of Morgan, Utah, by Arms Technology, Inc. of Salt Lake City.

The first Buck Mark had a simple stamped rear sight. A more heavy-duty, somewhat adjustable rear sight appeared several years later for target pistols. Then Joe Badali developed a new rear sight for target models that was much more durable than previous Browning adjustable sights. Introduced in 1992, the new Pro-Target Sight was more user-friendly for several reasons. The new rear sight offered finer adjustment and significantly more surface area contact between the grooves in the adjustment screws and the captive detents. This substantially improved the lifespan of the sight as well made sight adjustments much more positive. Improved metallurgy also improved sight life. Although originally designed for the Buck Mark Silhouette pistol, the new sight proved to be so outstanding—and so economical to produce—that it became standard issue on all models within the Buck Mark line, including the pistol AAC uses to create the Dragonfly.

Another big improvement of the Buck Mark over the Challenger series was the superior trigger mechanism, which quickly became known for its crisp let-off as well as lack of creep and play. The sears of all two dozen or so variants currently in the Buck Mark line are stoned for smoothness. Some target models feature fully adjustable triggers with stops to eliminate overtravel.

The Browning Buck Mark Camper model pistol that is used by Advanced Armament as the basis for its integrally suppressed Dragonfly pistol is Browning’s answer to the Ruger KM-512 and KMK-512 pistols. The Buck Mark represents nearly twice evolutionary history as the Ruger pistols. The Browning Camper is a competitive and timely pistol that entered the marketplace in 1999. The Camper is the product of a timeless design being improved gradually by generations of inspired designers over the course of nearly a century.

Silenced Pistol Performance

Performance of AAC’s Dragonfly was compared to unsuppressed and suppressed benchmarks. Unsuppressed benchmarks included the Browning Buck Mark Challenger and the Ruger Mark II. The suppressed benchmarks included AAC’s integrally suppressed Ruger known as the Phoenix pistol. The benchmarks were shot the same day as the Dragonfly, and these data were compared to an earlier test of the Phoenix. This study employed the testing regimen and equipment used by Paulson (1996) as amended by Paulson, Parker, and Kokalis (2002). I should also note, for the record, that when I gave Browning the opportunity to critique this article before publication, they still wanted to recommend cleaning the Buck Mark every 500 rounds for optimum performance, despite the fact that the gun can go for 1,500 rounds with clean ammunition.

The peak sound pressure levels (SPLs) of suppressed and unsuppressed pistols are reported in Table 1. Net sound reductions appear in Table 2. Muzzle velocities appear in Table 3. The percentage of velocity retained by suppressed pistols, compared to unmodified KMK-512 variant of Ruger Mark II pistol, appear in Table 4. Accuracy data appear in Table 5.

Did I find anything that I didn’t like that doesn’t appear in the data? I did find one nitpicking detail inherent in the Woodsman/Buck Mark lineage. This final observation relates to the fact that the receiver is open on both sides, which enables the back pressure of combustion gases to keep the Browning action much cleaner than a Ruger action. There is no free lunch. The gas and gunk have to go somewhere. The more open receiver design liberates gas and particulates toward both of the shooter’s forearms when using a two-handed stance. Also, a warm powder charge may open the bolt prematurely and direct effluvium toward the shooter’s face upon rare occasion via the open receiver. Therefore, eye protection (which should be mandatory anyway) is doubly advisable with this design.

In terms of handling the Dragonfly, the first thing one notices is its conspicuous lack of weight. This is a good thing for folks without musculature developed for handgun shooting, since it will reduce shooter fatigue and significantly extend shooting sessions. Although I prefer more weight to steady my aim upon firing, I quickly adapted. I consistently hit a 2-inch swinging metal target at 25 yards, shooting rapid fire from the standing offhand position. This was comparable practical accuracy to AAC’s Phoenix pistol fired on the same day. The same Phoenix delivered 0.57-inch groups with Remington HV ammo when fired from a Ransom Rest (see Table 4). A Browning Buck Mark insert for the Ransom Rest could not be obtained in time for this study to provide a rigorous analysis of the Dragonfly’s intrinsic accuracy.

In terms of sound reduction, it is interesting that the ultralight Dragonfly was only 1 decibel louder than the Phoenix shot on the same day under the same weather conditions, regardless of the ammunition used. The Dragonfly delivered an impressive 35 dB sound reduction with Remington High Velocity ammo, and it did so while delivering a muzzle velocity of 1,005 fps. That’s virtually the ideal velocity (1,000 fps) for providing the optimum mix of penetration, flat trajectory, and lack of ballistic crack over a wide range of temperatures. Achieving solid sound reduction without overly reducing projectile velocity is a most welcome design decision for anyone who may use the Dragonfly for hunting, animal control, or the selective destruction of objects (if one is an armed professional). Advanced Armament gets bonus points for optimum projectile velocity. It is also interesting that the Dragonfly retains a slightly larger percentage of velocity—compared to an unmodified parent pistol-than the Phoenix.

AAC gets higher marks for the 40 dB sound reduction delivered by standard velocity and subsonic ammunition. A suppressed .22 pistol that delivers 40 dB or more sound reduction has entered the realm of the Holy Grail.

Using the sound of the bolt closing on an empty chamber at 52 degrees Fahrenheit as the yardstick, AAC’s Dragonfly had an action noise of 110 dB, while AAC’s Phoenix had an action noise of 109 dB. Using subsonic fodder, the Buck Mark/Dragonfly delivered a mean (average) sound signature that was within 3 dB of action noise. The Ruger/Phoenix produced mean sound signatures that either equaled or were 1 dB louder than action noise, depending upon temperature. This is dandy performance.

Both the Dragonfly and the Phoenix get serious bonus points because they cycle flawlessly with subsonic fodder. Not every integrally suppressed pistol does, particularly if they have aggressive barrel porting.

What’s the bottom line? Advanced Armament’s Dragonfly integrally silenced Browning Buck Mark pistol is handsome, lightweight, quiet, accurate, user-friendly, relatively maintenance-free compared to a silenced Ruger, and downright fun. The Dragonfly is a lot of pistol for $795 retail (or $695 for a silenced barrel assembly with front sight). I give Advanced Armament’s Dragonfly two enthusiastic thumbs up.

Literature Cited

Browning, John, and Curt Gentry. 1964. John M. Browning; American gunmaker. Doubleday & Company, Inc., New York. 323 pp.

Browning, John, and Curt Gentry. 1994. John M. Browning; American gunmaker. Second edition. Browning Arms Co., Morgan, UT. 390 pp.

Paulson, A.C. 1996. Silencer history and performance. Volume 1. Sporting and tactical silencers. Paladin Press, Boulder, CO. 424 pp.

Paulson, A.C, N.R. Parker. 2002. Silencer history and performance. Volume 2. CQB, assault rifle, and sniper technology. Paladin Press, Boulder, CO. 429 pp.

Smith, W.H.B. 1966. Book of pistols and revolvers. Sixth edition. Stackpole Books, Harrisburg, PA. 752 pp.

Sources

Advanced Armament Corp.
Dept. SAR
3100 Five Forks Trickum Road SW, Suite 201
Lilburn, GA 30047
Phone 770-985-3109
Fax 770-985-3110
Website: www.advanced-armament.com

Aero Peltor
Dept. SAR
90 Mechanic Street
Southbridge, MA 01550
Phone 508-764-5500
Fax 508-764-0188

Browning Arms Co.
Dept. SAR
One Browning Place
Morgan, UT 84050
Phone 801-876-2711
Fax 801-876-3331
Website: www.browning.com

Greg Cartmell
Cartmell Gallery
609 22nd Avenue
Meridian, MS 39301
Phone 601-485-1122
Website: www.cartmellgallery.com

By Al Paulson

Heckler & Koch decided to develop a pistol suitable for international competition in the realms of IPSC (International Practical Shooting Competition) and other so-called “practical” competitions. Developed with the help of several internationally successful competitors, HK’s first foray into this field produced a pistol called the USP Expert, which was introduced in 1998. The new pistol delivered superior accuracy by combining the best features of the USP Match, USP45 Tactical, and the Mark 23 in chamberings that included 9x19mm, .40 S&W and .45 ACP. HK subsequently stretched the 9x19mm and .45 ACP variants of the Expert to create the USP Elite, which features a 6-inch barrel. Both the Expert and Elite accept high capacity magazines (18 rounds in 9mm). The slide is contoured in a distinctive fashion forward of the frame to reduce weight and improve balance. Thanks to the U.S. ban on large-capacity magazines, and the fact that these guns are optimized for high-cap magazines, the Expert and Elite are not imported through normal channels. They do sometimes trickle in as GI bring-backs, however, as we shall see. I was very pleased to have the opportunity to borrow both 9x19mm Expert and Elite pistols for a hands-on evaluation.

The general design characteristics and accuracy of the 9x19mm Expert and Elite pistols are compared in Table 1.

HK Expert Pistol

The USP Expert has been performing very well indeed among European IPSC shooters, thanks in large part to its inherent accuracy and large-capacity magazines. The USP Expert features hexagonal polygonal rifling with a right hand twist rate of one turn in 250 mm. Polygonal rifling provides a better gas seal than conventional land-and-groove cut rifling, less barrel fouling, and longer barrel life. The Expert employs the now recognized and accepted O-ring bushing system. The barrel on the USP Elite features the Mark 23’s type of elastomer O-ring just behind the muzzle. The O-ring provides an interface between the barrel and slide that significantly improves the weapon’s accuracy. While this might seem like a weak link in the system, the O-ring has a demonstrated lifespan in excess of 20,000 rounds. Simply oil the O-ring after cleaning the weapon and replace if necessary. The pistol will function normally without the O-ring in a life and death emergency, but shooting it without an O-ring will eventually damage the barrel/slide interface. Specifically when shooting without an O-ring, the groove in the barrel will hammer at the slide’s muzzle opening, so extended shooting without the O-ring will permanently damage the slide.

The 9x19mm Expert accepts 18-round magazines, while the .40 S&W variant takes 16-round magazines, and the .45 ACP Expert takes 12-round magazines. The speed of magazine changes is enhanced by a beveled, extended magazine-well that HK Oberndorf calls a Magazintrichter in German. That literally means “magazine funnel”, but HK Oberndorf officially calls the mag well a “Jet Funnel” in English. The Jet Funnel can be removed, so residents of the United States can use restricted capacity 10-round magazines. I have no doubt that reducing U.S. competitiveness in international IPSC competition by limiting magazine capacity makes all our American children quite safe from latent psychopaths and terrorist sleepers. I’m also sure this legislation makes congressfolk sleep more soundly at night. My fellow Americans: let the joy of your sacrifice gladden your hearts as you abstain from the Elite’s wonderfully evil and efficient 18-round magazines in favor of the righteous and legally mandated 10-rounders that force you to plummet from First Place to 300th when competing overseas. All American practical pistol shooters must make this one small sacrifice. For the children.

Presentation of the HK Elite from the holster is facilitated by the fact that the rear of the slide has been milled down to lower the profile of the large, adjustable match rear sight. The rear sight features micrometer adjustments for windage and elevation. Balance is facilitated by the long slide, which also gives a long sight radius of 7.5 inches. Accuracy is not only enhanced by the aforementioned O-ring in the barrel, but also by a match grade single-action/double-action trigger. An ambidextrous safety enhances safety and performance in events where the shooter must engage targets with the weak hand. An extended slide release lever and an ambidextrous magazine release facilitate rapid magazine changes. Other nifty features include an extractor that also functions as a loaded-chamber indicator, HK’s patented recoil-reduction system that is standard in full-sized USP variants, and an adjustable trigger stop.

The trigger stop limits trigger travel after the sear releases the trigger. This enhances practical accuracy. Adjustments can be made with a 1.5 mm socket wrench that is supplied with the pistol. Turning the setscrew in the trigger clockwise will reduce overtravel, but care must be taken to ensure that the screw is not adjusted so far that the trigger stop prevents the trigger from functioning in both single action and double action modes.

The incorporation of the USP’s recoil-reduction system should come as no surprise because the Expert is very similar to the USP9 (which was introduced in September 1993). Both are chambered for the 9x19mm cartridge. While these pistols feature a polymer frames and hammer-forged barrels, they are basically pistols of traditional design adapted to modern materials and manufacturing processes. They operate by a using a modified Browning short-recoil, locked-breech system that is a well-established linkless design. The dropping barrel locking system is similar to the design of the Ruger P90 and SIG-Sauer P266, among others. In the locked position, a large block above the barrel’s chamber engages the ejection port in the slide. The P35, on the other hand, uses Browning’s locking grooves milled into the barrel and slide to lock the breach during the high-pressure phase of the action cycle.

Upon ignition, combustion gases simultaneously push the bullet down the barrel and the empty case backward against the breech face. I realize that’s a penetrating glimpse into the obvious, but we do need to begin at the beginning. This rearward force pushes the slide and barrel backward for about 3 mm (0.1 inch) until a lug underneath the chamber engages a hooked locking surface at the rear of the guide rod, which is a part of what H&K calls the recoil/buffer spring assembly. As these angled surfaces fully engage, the rear of the barrel is pulled downward, which causes the locking block above the chamber to disengage from the ejection port. The slide then continues its rearward movement to complete the extraction, ejection and reloading sequence.

The innovative recoil/buffer spring assembly is a particularly interesting aspect of the engineering found in the Elite, Expert and other USP variants. It actually works coming and going. The robust guide rod has two captive springs: a full-length recoil spring and a short, smaller diameter buffer spring just in front of the hooked locking lug at the rear of the guide rod assembly. The latter spring buffers the barrel as it unlocks from the slide. This can reduce measured recoil by as much as 30% with +P ammunition, although the relatively high axis of the barrel in USP variants tends to exaggerate felt recoil.

Other similarities between the Elite and USP9 with the Browning’s 9mm Hi-Power and his older .45 ACP M1911A1 include a grip angle identical to the M1911A1, and the placement of the slide release, magazine release, and control lever in the same relative place as each of these older pistols. On Browning pistols, this control lever functions as a safety: UP for SAFE and DOWN for fire.

The control levers on most USPs work in a similar fashion, although there are ten basic variations on that theme. Table 2 lists nine of the ten variants based upon published HK data and my own guess as to the tenth. The precise control lever function employed for so-called Variant 8 is not listed in official HK literature I’ve seen.

Note from Table 2 that Variant 1’s trigger and safety system features a SA/DA trigger with a safety lever on the left side of the grip. The control lever has both a safety and decocking function. Safety markings are on the control lever, and a white index mark on the frame points to which feature is engaged. Pushing the lever fully upward engages the safety and index mark points to a white S for SAFE. The slide can still be manipulated (a round can be loaded) with the weapon set on SAFE. Push the lever down and the index mark points to a red F for FIRE. To decock, simply push the lever below the F position to drop the hammer. Both the Expert and the Elite are supplied overseas with spare “detent” plates that allow the user to convert the safety lever to DECOCKING operation only with no safety engagement.

The Expert and Elite incorporate several additional safeties. The hammer system features a lever that rotates upward when the trigger is pressed; this action depresses the spring-loaded firing spring safety and allows the striker to move forward. The pistol also incorporates a passive disconnector safety.

The USP Expert also differs from its Browning heritage because the Expert’s magazine release differs from Browning designs in that it does not take the form of a push button, but rather a small lever that is pushed down to release the drop-free magazine. For most shooters, this represents better human engineering than Browning’s button on the M1911A1 and P35, especially when the operator has gloved hands. I have small hands and must shift the grip of the firing hand in order to manipulate the magazine release with the thumb. Most operators with small hands manipulate the release with their trigger finger, which does not require shifting the hand on the grip and has the additional benefit of ensuring that the finger is off the trigger and outside the trigger guard during the magazine change.

The injection-molded polyamide frames of HK’s Expert and Elite pistols are reinforced with microscopic glass fibers that constitute 15% of the frame’s material. This polymer has a better tensile strength than aluminum and it’s lighter than steel. Polyamide also resists chemicals, high temperatures, and corrosion. Four short steel rails (two on each side) are molded into the polymer frame to guide the slide much like a Glock pistol.

A key feature of both the Expert and Elite frames is the modular, oversized beveled magazine well that facilitates magazine rapid magazine insertion under stress. Unfortunately, honest citizens of the United States cannot use the wonderful 18-round magazines intended for HK’s 9mm Expert and Elite pistols thanks to mindless, feel-good provisions of the infamous Violent Crime Control and Law Enforcement Act of 1994 (Public Law No. 103-322, 108 Stat. 1796), which banned the manufacture of magazines with a capacity greater than ten rounds for private ownership. While the presence of the Jet Funnel prevents the use of HK’s 10-round magazines, HK Oberndorf was thinking ahead and made the extended magazine-well modular and easily removable, so that 10-round magazines could be used in the Expert and Elite in the States.

In terms of handling characteristics, the 9x19mm USP Expert balanced extremely well and the long slide made the Expert a remarkably stable platform. Between the match-grade trigger and its trigger stop, shooting this handgun provides more of a religious experience than a shooting experience compared to other premium out-of-the-box 9x19mm pistols such as HK USPs, the Beretta M9/92F series, and the Walther P99. The Expert’s polymer frame, long and heavy slide, and the recoil reduction system—plus the small 9x19mm cartridge—make recoil a nonissue.

Since the Germans commonly use 123-grain FMJ ammunition for accuracy testing, this study used Hornady’s outstanding 124-grain JHP/XTP ammunition. Shooting the user-friendly Expert in double-action/single-action mode at 25 yards, the pistol delivered five-round groups averaging 1.5 inches. Other premium 9mm out-of-the-box pistols I’ve tested over the years generally delivered 2-3 inch groups at that distance. In terms of confidence-inspiring balance and other handling characteristics, match trigger, and outstanding accuracy, shooting HK’s 9x19mm USP Expert will raise the bar considerably for the serious practical shooter. HK’s USP Expert is the penultimate out-of-the-box 9mm target pistol in my experience.

HK Elite Pistol

Heckler & Koch did not rest on its laurels after creating the impressive USP Expert target pistol, but rather forged ahead to create the even better USP Elite pistol by stretching the Expert’s 5.2 inch barrel to 6.0 inches, which required designing a sleek new target slide. The Elite’s slide is hand-fitted to the frame to achieve maximum accuracy. Available thus far in 9x19mm and .45 ACP, the USP Elite pistol is designed to take 18-round 9mm magazines and 12-round .45 mags. Like the Expert, the Elite features a match trigger with trigger stop, and target sights with fully adjustable rear sight. The barrel employs the same elastomer O-ring as the Expert, located just behind the muzzle as an interface between the barrel and slide that significantly improves the weapon’s accuracy. Trigger and control lever functions are the same as the Expert, as is the recoil reduction system. A modular Jet Funnel speeds magazine changes, and the extended magazine-well can be easily removed to use 10-round magazines.

In terms of handling characteristics, while the Elite is 3 ounces heavier than the Expert, it balances better in my hands. That is a considerable achievement, because the Expert’s balance is wonderful. The longer sight radius of the Elite will be an advantage for young eyes and a disadvantage for tired old eyes, with one curious caveat. The longer sight radius of the Elite combined with my progressive multifocals allow me to maintain a more natural and comfortable head angle when shooting the Elite, compared to the Expert.

In terms of performance, shooting the Elite in double-action/single-action mode at 25 yards, the pistol delivered five-round groups averaging an impressive 1.3 inches with my Hornady’s outstanding 124-grain hollow point ammunition.

There is such a thing as love at first sight. A vision of graceful lines, proportion and manner that stir the soul, form a wistful smile on the face, and conjure a silent note of gratitude to the gods. Besides the all-important smile that melts your heart, there are the artistic yet functional creations of the human spirit that appear so beautiful on so many levels that you know deep in your bones that this creation approaches perfection. Somehow, when an old salt sees a truly beautiful sailboat, the seafarer knows that sailboat will function as good as it looks. When a pilot sees a beautiful sailplane, the aviator knows that aircraft will soar circles above and beyond the norm. To the seasoned mind, beauty becomes the sum of a lifetime of experience, a complex equation factoring in many variables related to projected performance in a host of real-world situations—as well as simple aesthetics. As one first handles the USP Elite, this pistol designed for practical pistol competition appears to have the graceful lines, proportion and manner comparable to the finest sailboat or sailplane. It is an artistic achievement of consequence that holds the promise of great practical performance in the real world. In terms of real-world performance, HK’s USP Elite delivers on that promise. It is the ultimate out-of-the-box 9mm target pistol in my experience.

Advanced collectors who would like to own an HK Expert or Elite pistol should contact Capital City Firearms. From time to time, they purchase NIB GI bring-backs of these pistols and offer them for sale. For outstanding holsters, cases, and web gear in use by many elite military and government organizations, contact the London Bridge Trading Company, Inc.

Capital City Firearms
Dept. SAR
P.O. Box 29009
Richmond, VA 29009
Phone 804-740-4926
Fax 804-740-9599
Website www.ccfa.com

Hornady
Dept. SAR
P.O. Box1848
Grand Island, NE 68802
Phone 800-338-3220
Fax 308-382-5761
Website www.hornady.com

London Bridge Trading Company, Ltd.
Dept. SAR
3509 Virginia Beach Blvd.
Virginia Beach, VA 23452
Phone 757-498-0207
Fax 757-498-0059
Website www.londonbridgetrading.com

By Al Paulson

While the oldest working pistol silencer probably dates back to a French design from about the time of the Franco-Prussian War of 1870-1871, and the first silencer patent dates from 1899, Hiram Percy Maxim’s Model 1909 silencer was the first commercially successful silencer in the world. I recently stumbled across a Maxim Model 1909 silencer fitted to an apparently hand made, one-of-a-kind single shot pistol that had been in continuous use for killing cattle at a slaughterhouse in Texas since 1909. The Maxim was still going strong, having survived a 91-year torture test. I have never run across a silencer that has been in continuous service for anywhere nearly as long as this particular specimen. This Model 1909 served as a working tool, not as a collectable historical artifact, from 1909 until 2000. Clearly, Hiram Percy Maxim could build a robust silencer. Furthermore, the level of performance, even after nearly a century of steady use, will be surprising.

The dawn of the 20th century brought a new phenomenon to modern life: noise pollution. While referring to noise as “pollution” would not happen for generations to come, the reality was that the amount of noise assaulting the senses was growing exponentially throughout the United States at the dawn of the 20th century, adding very real stress to urban life in the Golden Age. Street cars, gas engines, motor cycles, motor cars, motor boats, recorded music, steam exhausts, assembly lines, and Diesel engines added to the gentler, more traditional sounds of trains and horse-drawn carriages and wagons. Some New England mills were so noisy that they tormented people ten miles away. The country swelled with a great wave of immigration, and the population pushed outward from urban centers, where they tended to find the ubiquitous American pastime of shooting a disquieting and intrusive form of noise pollution.

Maxim firmly believed that noise could wreak havoc on the human nervous system, a belief that has been confirmed by a nearly century of subsequent medical research. Maxim declared a personal war on noise. In 1906, he designed a firearms silencer for a .30-30 rifle based upon the principle of creating a whirlpool of gases inside the silencer, like water going down the drain of a bathtub, leaving a neat little clear hole through which a bullet could travel unimpeded. This led to the development of the Model 1908 silencer, which was patented in 1909.

The Model 1908 looked something like a conch shell stuck on the end of the Winchester lever-action rifle. It was a less than stellar performer. Undaunted, Maxim’s experiments revealed that simply creating turbulence inside the suppressor to slow the gases and delay their release from the silencer worked very well.

This revelation eventually led to the development of the Maxim Model 1909 silencer, which was patented in 1910. A prolific writer, Maxim continued his war against noise by adding a second front: a campaign to win hearts and minds with a series of articles discussing his view that noise was one of the principal problems of the day. He also began an advertising blitz (to borrow a phrase from the next generation) extolling the virtues of the Maxim Silencer in the mainstream magazines of the day, including the likes of New Yorker Magazine, Scribner’s, Popular Mechanics, McClure’s, Redbook, Yachting Magazine, and the National Sportsman.

The Maxim Model 1909 was replaced a year later by the improved and more compact Model 1910. Most historians have referred to the Model 1910 as the finest of Maxim variants. Nevertheless, after having shot a variety of Maxim Model 1909 silencers on a variety of .22 pistols and rifles, I have developed a particular respect for the Model 1909. It may be a bit bulky, but it does perform.

The Maxim Model 1909 silencer is an eccentric design fabricated from soft, malleable steel baffles and tubing, with a machined rear end piece that serves as the mount and rear end cap. The Model 1909 variant evaluated in this study measures 4.88 inches overall, while the tube length is 4.55 inches. The tube diameter is 1.35 inches and it is press fit into the machined rear end cap, where a rivet on the left side of the rear end cap secures the tube in place. Two pressed grooves around the circumference of the tube toward the rear of the suppressor secure thick blast baffles, while one 3.77 inch longitudinal groove running along the bottom of the tube aligns the asymmetrical baffles. The exit hole in the front baffle, which serves as a press fit end cap secured by rolling the suppressor tube inward at the front end, measures 0.31 inch. The mount in the rear end cap features 1/2×20 TPI interrupted female threads for screwing onto a threaded barrel. The suppressor weighs 6.8 ounces. Once blued, the finish is well worn. The top of the machined rear end cap is stamped “22 CALIBRE” and the rear face of the rear end cap is stamped:

MAXIM SILENT FIREARMS CO.
NEW YORK
PATENT MARCH 30, 1909

The patent date stamped on the silencer is a bit misleading. The date actually refers to U.S. Patent 916,885 for the Model 1908 silencer. The patent application for the Model 1909 silencer was submitted on October 8, 1908 but U.S. Patent 958,931 was not granted until May 24, 1910. The suppressor was registered as required after the National Firearms Act was passed in 1934 and carries an “IRS” prefixed serial number.

The hand-made single-shot pistol is a side-break design featuring a pull-cock striker. The overall length of the pistol is 9.25 inches, and maximum height is 4.65 inches. Barrel length is 6.97 inches. The receiver is 0.73 inch thick, the walnut grips are 1.16 inches thick, and the pistol weighs 24.0 ounces without the Maxim silencer. The barrel is threaded 1/2×20 TPI to accept the Maxim suppressor. Design of the pistol is robust and thoughtful, and the trigger nothing short of awesome. Trigger pull is a remarkably crisp 4.3 pounds, breaking like the proverbial “glass rod” (a wonderfully descriptive but horribly hackneyed expression I’m using here with great circumspection, for only the second time in my life, since no other turn of phrase really fits).

Contrary to conventional wisdom that the Model 1910 was a better silencer than the Model 1909, I discovered during informal shooting of this handmade single-shot pistol that the Model 1909 seemed noticeably quieter than my memory of the Model 1910. The Model 1909 seemed to provide both lower sound signatures and a softer sound with less of a hard, uncorking component. To test this hypothesis, I arranged to test fire the Model 1909 on a vintage Colt Woodsman (production began on March 29, 1915) fitted at the factory with a sleeve adapter to accept a Maxim silencer on the pistol’s 6.5 inch barrel. I compared the performance of the Model 1909 suppressor with a Maxim Model 1910 on the same afternoon using Remington high velocity (HV), standard velocity target (SVT) and subsonic ammunition at a temperature of 88 degrees Fahrenheit. Table 1 compares the sound signatures measured 1 meter to the left of the muzzle or silencer, expressed as decibels (dB). Table 2 provides the net sound reductions.

To look the relevant data at from a historical perspective, in terms of what Hiram Maxim experienced himself during the Golden Age before the outbreak of the Great War, one should consider only the data for standard velocity ammunition. The first high velocity .22 rimfire cartridge was not introduced until 1930 (by Remington, as it turns out), and .22 subsonic ammunition did not appear until relatively recently. The data show that the Maxim Model 1909 significantly outperforms the Model 1910 with both period-equivalent and modern ammunition, beating the Model 1910 by 8-10 decibels. That’s a whopping big difference when you consider that the decibel scale is logarithmic rather than linear.

Furthermore, the data—including the high velocity and subsonic numbers—also show that the Model 1909 performs very well by modern standards, delivering 30-33 dB net sound reductions, depending upon ammunition. Finally, this Maxim Model 1909 silencer survived a 91-year torture test of regular work in a slaughterhouse. The silencer kept animals waiting their turn from becoming alarmed and unmanageable, making the process more humane. The silencer also protected generation upon generation of workers from hearing loss.

While the Maxim’s blued finish is a distant memory, the can remains robust after countless thousands of rounds and nearly a century of use. Considering its excellent structural condition today, I see no reason why this Maxim Model 1909 cannot deliver another 91 years of service. If we assume (30 cattle killed/day) (5 days/week) (52 weeks/year) (91 years) = 709,800 rounds fired through this old veteran thus far.

Underrated and largely overlooked by historians, it turns out that the Model 1909 silencer represents one of the most remarkable achievements of a remarkably influential and insightful man. Hiram Percy Maxim’s Model 1909 silencer must be considered one of the greatest suppressor designs of all time.

“The long answer to explain my interest, Tom, begins back in the 1980s, when I established what I believe to be the first privately owned laboratory designed for the scientific measurement of sound suppressor performance. With a lot of help from scientists, suppressor industry leaders, and end-users from around the world, I put together the equipment and a testing regimen that could provide a scientific comparison of competing suppressor designs. The net result of subsequent research that has been conducted over the years is that end-users are no longer satisfied with subjective platitudes like ‘that silencer was real quiet’ or ‘it sounded like a Mercedes door closing’ or ‘the report was just a loud cough.’ Now, for better or worse, people want numbers. They want to know the suppressed sound signature and the net sound reduction produced by a silenced firearm.

“That’s good. In fact, that has been my goal from the very beginning: to provide objective scientific data akin to accuracy testing of firearms, what a scientist would term ‘hard data’ based upon repeatable experiments. Both manufacturers and end-users now have an objective methodology for comparing silencers. Today, manufacturers and even a number of military end-users around the world use the methodology I developed and popularized.

“But I may have created a monster. I’ve continually pointed out since the beginning of this quest that there are a lot of other factors in a silencer’s performance equation besides decibels. The amount of length and weight a suppressor adds to a firearm are critical factors for both tactical and sporting applications of silenced firearms. Diameter is crucial if one must use factory iron sights. Additional factors that may be critically important in the decision to purchase and deploy a given silencer design include: compatibility with a wide variety of ammunition, reliability of the parent weapon when a given silencer is attached, positive or negative effects on accuracy, durability, service life, maintenance requirements, purchase price, life cycle cost analysis, user-friendliness, and availability to a given category of end-user. For the private collector, pride of ownership is also a significant factor in the selection of a sound suppressor, and people tell me your CAC line of suppressors engenders that pride of ownership.”

The conversation went on for more than an hour, with Tom agreeing to loan me one of each caliber CAC suppressor for evaluation. The only potential fly in the proverbial ointment was that Craig Wheatley at Tactical Innovations Inc. was so impressed by the CAC 45 suppressor that he purchased the entire production run of CAC 45s for resale. So I arranged to borrow a specimen from a gracious Mr. Wheatley for this study.

The Bowers CAC .45 suppressor, like all CAC variants, is made from 1.75 inch aluminum tubing. This standardization, plus the fact that Bowers bought a third of a mile of tubing, was a major factor in keeping the retail price of standard CAC cans to $295. So was the fact that the aluminum frusto-conical baffles were mass produced in house on a Hardinge CNC turning center in such quantities that Bowers had two 55 gallon drums full baffles after his 9mm production run. Like its 9x19mm sibling, the CAC 45 is 11.25 inches long. It weighs 19.2 ounces. The suppressor can be disassembled for cleaning or maintenance, which is a warm fuzzy for many private collectors. The front end cap of the CAC 45 suppressor features extra spanner holes in a circular pattern similar to the one first conceived by Tim Bixler of SCRC, providing extra holes should the first pair become damaged over the years during disassembly. A spanner is not provided with the Bowers suppressor, however, in an effort to keep the price down. Normal cleaning can be accomplished by immersion in a suitable solvent such as mineral spirits or Varsol, so disassembly should not be required. It is also noteworthy that Bowers offers a lifetime warranty on the baffle stack.

Between the clearly robust, business-like construction, especially nice black anodized finish, and particularly handsome laser engraving, the Bowers CAC 45 sound suppressor exudes the gravitas of a serious working tool and the workmanship worthy of the demanding collector, at a bargain price.

So far so good. How does it perform? I examined the performance of the Bowers CAC 45 on an Ingram M10 submachine gun manufactured by RPB, using Black Hills 230 grain FMJ ammunition. Black Hills ammunition is noteworthy for its quality, accuracy and consistency, and it has become my reference standard in all available calibers for testing and evaluation. I also use Black Hills ammunition for my personal concealed carry handguns.

I compared the CAC 45’s performance to a Cobray M10 suppressor that was retrofitted in the late 1980s with a baffle kit from one of the major manufacturers. The kit replaced WerBell’s spiral diffusers and wipe with stamped baffles and spacers, and a reflective front end cap. This retrofitted M10 suppressor has an overall length of 11.5 inches and a weight of 27.2 ounces. The suppressor’s rear tube has a diameter of 2.22 inches, while the front tube has a diameter of 1.75 inches. The reflective front end cap has a bore of 0.57 inch, while the CAC 45 has a bore of 0.54 inch.

The retrofitted M10 eliminates the wipe with its need for periodic replacement, it provides better accuracy, and provides 1 dB better sound reduction. The only downside is that the sound signature seems harsher because there is a hard uncorking component to the sound, while the original WerBell design has a longer and softer sound that is actually more pleasing to the ear. Furthermore, the original WerBell’s softer sound signature seems less like a sound one might have to worry about.

I compared these two traditional suppressors for the Ingram M10 with the Bowers CAC 45, measuring the sound pressure levels (SPLs) in two locations: (1) 1.00 meter to the left of the muzzle or front of the sound suppressor, as appropriate, and (2) at the shooter’s left ear. Details on the testing regimen can be found in Chapter 5 of Volume 1, Silencer History and Performance. The mean (average) sound signatures appear in Table 1 and the net sound reductions appear in Table 2, confirming several suspicions I’ve kept to myself until this point in the discussion. The first is that .45 caliber submachine guns are hard to suppress. The second is that the CAC design seems really optimized for 9mm cartridges; I’d expect double the sound reduction out of the 9mm variant.

Looking Beyond the Decibels

What the numbers don’t show is the profound difference in subjective performance between the Bowers CAC 45 and the Cobray M10 retrofitted with baffles. The Cobray silencer produced a high-pitched, sharp uncorking sound. The Bowers CAC 45 produced a soft, low-pitch, relatively long depressurizing sigh that makes the CAC 45 much more comfortable to shoot than the sound pressure levels might suggest, since a significant portion of the sound energy seems to be below the frequency of peak hearing sensitivity in humans.

The sound pressure level at the shooter’s ear is 1 dB over the European Risk Limit for hearing loss from impulse sound and is equal to the pain threshold for impulse sound. The rule of thumb is that if a sound hurts, it is already above the safe limit. Yet shooting the CAC 45 did not hurt, presumably because the can shifts much of the sound energy to below the peak sensitivity of the human ear. Therefore, the amount of sound suppression is probably enough to safeguard the operator’s hearing, and it will certainly be safe for someone an armspan behind the shooter’s ear.

The Bowers CAC 45 also proved much better at recoil reduction during full-auto fire than the Cobray M10 retrofit, providing significantly better hit probability. The Bowers CAC also delivered much better accuracy at 25 yards with semiautomatic fire, producing an average of 2.70 inch groups, while the M10 retrofit delivered an average of 3.81 inch groups. That’s just part of the Bowers accuracy advantage. At 25 yards, the Bowers groups centered an average of 2.6 inches from the point of aim up and to the right to the 1 o’clock position, while the M10 retrofit groups centered an average of 4.3 inches to the 1 o’clock position. Thus, the Bowers CAC 45 provided a 29 percent advantage in terms of group size and a 40 percent advantage in terms of shot placement over the M10 retrofit, which is itself significantly more accurate than an M10 with fresh wipe. This adds up to about a 70 percent increase in accuracy or effective range when using the CAC 45 compared to the Cobray M10 with baffle retrofit kit. Since the point of shooting, whether one is a sport shooter or an armed professional, is hitting the target, the big news for me personally is how well the Bowers CAC 45 improves accuracy over the traditional competition.

Final Thoughts

So what’s the bottom line here? Tom Bowers had the goal of producing suppressors for submachine guns of Ingram heritage that provide just enough suppression, maximum durability, and minimum price. He succeeded admirably. The Bowers CAC 45 sound suppressor provides an especially nice black anodized finish and particularly handsome laser engraving that will provide the pride of ownership demanded by the serious collector. The CAC 45 also features the robust, business-like construction required of a working tool. The suppressor seems to generate enough frequency shift to not only create a pleasing sound signature, but also to just barely safeguard the operator from short-term and long-term hearing loss. The CAC 45 suppressor also delivers significantly better accuracy and effective range than Mitch WerBell’s M10 sound suppressor, whether or not the M10 is fitted with a baffle retrofit kit. Furthermore, the CAC 45 is a half-pound lighter than the upgraded M10.

Finally the bottom line to the bottom line ain’t bad either: this is a lot of silencer for $295 retail. Clearly, decibels aren’t always the whole story. That’s an important lesson. The late astronomer Carl Sagan would have called that a Big Truth. After this enlightening study, I’ve purchased a Bowers CAC 45 myself, and I plan to retire my M10 retrofit. That is the highest recommendation I can possibly make for the Bowers CAC 45.

To buy a Bowers CAC 45 suppressor, or a new or used MAC submachine gun, contact Craig Wheatley at Tactical Innovations Inc., Dept. SAR, 108 Holsum Way #D7, Glen Burnie, MD 21060; phone 410-760-3609; website www.tacticalinc.com/. For information on other Bowers suppressors, check out Tom Bowers’ website at www.subguns .com or go directly to his suppressor page at Bowers, P.O. Box 430, Cornelius, OR 97113; e-mail subguns@subguns.com; website www.subguns.com/products/cans. I’ll continue to report on the other suppressors in the Bowers line at the earliest opportunities. If your local retailer does not stock Black Hills ammunition, you can purchase it directly from Black Hills Ammunition, Inc., Dept. SAR, P.O. Box 3090, Rapid City, SD 57709-3090; phone 605-348-5150; fax 605-348-9827; website www.black-hills.com.

Gemtech’s Mossad suppressor blends gracefully with the lines and proportions of the Uzi. Part of the reason is that the rear of the can duplicates the design of the Uzi’s barrel nut, so installation couldn’t be easier or more positive: simply remove the barrel nut and replace it with the sound suppressor. Part of the reason is that the suppressor extends back over the barrel to the receiver, which minimizes overall system length. And part of the reason is that the can is so light that it neither inhibits the speed of target acquisition nor adds to shooter fatigue. Clearly, such graceful integration with the weapon has significant functional as well as aesthetic merit.

Manufactured from precision CNC machined high tensile strength aluminum alloys, the Mossad has an overall length of 11.5 inches, a diameter of 1.38 inches, and a weight of just 12.5 ounces. Mounting the suppressor is very quick and requires no modification of the weapon. Simply remove the barrel nut and replace with the suppressor, which is locked into place by the spring-loaded barrel nut retention latch that engages the slanted teeth on the rear of the suppressor mount. This makes the Gemtech suppressors much safer to use than cans that simply screw onto a threaded barrel.

Performance

I tested the performance of Gemtech’s Mossad suppressor on a Group Industries clone of the Uzi submachine gun fitted with an FN bolt, using a variety of Black Hills Ammunition including 115 grain RN FMJ, 147 grain flat point FMJ subsonic, and a new specially designed submachine gun subsonic round that features a 147 grain round nose FMJ projectile. The standard 9x19mm subsonic round found in the Black Hills catalog features a flat point projectile with velocity optimized for pistols. This makes perfect sense because the vast majority of customers buying 147 grain ammo are agencies using the FMJ subsonic round as an affordable, ballistically equivalent training load to 147 grain hollowpoint duty ammo used in their pistols. This FP ammo is not desirable for use in submachine guns for several reasons. Since submachine guns have greater barrel lengths than pistols, conventional Black Hills subsonic ammo frequently generates a loud ballistic crack in subguns, negating the value of adding a silencer to the weapon if stealth is the goal. Furthermore, FP or HP ammo doesn’t feed reliably in weapons that feed like Ingrams and Uzis because of the abrupt feed ramps found in these submachine guns.

The new subgun ammo from Black Hills features a round nose for reliable feeding and a slower velocity for effective suppression in submachine guns over a more practical range of temperatures and barrel lengths. This new RN subsonic is not found in Black Hills literature but is being made available as a special service, and must be ordered directly from Jeff Hoffman, the president of Black Hills Ammunition. It is in stock as this was being written. This 147 grain RN FMJ ammo is highly recommended for all silenced submachine guns. (Contact Jeff Hoffman, Black Hills Ammunition, Inc., Dept. SAR, P.O. Box 3090, Rapid City, SD 57709-3090; phone 605-348-5150; fax 605-348-9827; URL http://www.black-hills.com).

I used a single lot of G&L 147 grain FMJ subsonic ammo for benchmark sound testing for much of the 1990s. It proved ideally suited for use in suppressed submachine guns in terms of projectile velocity, accuracy, reliable weapon function, and gracefulness when fired with a sound suppressor. This G&L round also works well in pistols. G&L ammunition is no longer available. Therefore, I began using the new Black Hills 147 grain RN FMJ as my subsonic 9x19mm reference standard when it became available in 1999. So that we all can get a feel for comparing recent with older research, this study provides comparative data using both the G&L and Black Hills subsonic 9x19mm ammo. Finally, I tested the Mossad with Israeli Samson 158 grain subsonic ammunition, which is used by the Brits for CT (counter-terrorist) operations and is imported into the States by Cole Distributing, Inc. (Dept. SAR, P.O. Box 50271, Bowling Green, Kentucky 42102; phone 270-622-3569; fax 270-622-3757; URL http://www.cole-distributing.com/).

The first thing that impressed me during the course of the testing was that the Mossad eliminated muzzle flash and muzzle climb, and it cut felt recoil in half. Furthermore, I was gratified that the suppressor never loosened during the course of the testing, unlike some suppressors that I’ve screwed directly onto threaded Uzi barrels. I was quite pleased with the satisfying sound signatures produced by the Mossad with both vintage G&L subsonic as well as the new 147 grain RN FMJ submachine gun round from Black Hills Ammunition. I was flabbergasted when I used the formidable 158 grain +P+ Samson subsonic round, for I would never have expected this much suppression from a compact muzzle can on an open-bolt gun. Clearly the advanced baffle design likes the ultra-fast powder of the Samson fodder, for this round produced far and away the quietest sound signatures (see Table 1) and the best net sound reduction (see Table 2). In fact, using the powerful Samson fodder made the Uzi with Mossad quieter than the venerable MP5SD. It is safe to say that this is outstanding performance.

Why was the Gemtech silencer the quietest with the most powerful round? The answer relates to the nature of the silencer’s design. The internal baffle structures use asymmetric surfaces to direct gas flow away from the central core of the silencer and other structures to increase turbulence. All of this is pressure driven. The higher velocity gases produced by the Samson round actually enable the structures inside the Mossad to work more efficiently.

It is also noteworthy that the Mossad dropped the SPL of supersonic ammo to well below the international safety limit of 140 dB, above which hearing damage is likely when a person is subjected to impulse sound while not wearing a hearing protection device. There are certain tactical applications, such as the anticipation of opponents wearing aramid fiber body armor, where the more slender supersonic projectiles make more tactical sense than subsonic rounds.

Final Thoughts

All of these numbers are interesting, but what do they mean in the real world? In order to see just how stealthy Gemtech’s Mossad could be in the real world, I fired a pair of Samson 158 grain FMJ rounds into the ground followed by a pair of BH 147 grain RN FMJ rounds with the selector set to R for repetition (i.e., semiautomatic), while my wife and teenager were watching TV inside a house of standard frame construction. I was three armspans outside of the back door, and they were three armspans inside. Neither lady heard a thing, so I’d say that the Mossad is sufficiently stealthy for missions faced by the armed professional in the real world or by the private individual who is simply interested in some sport shooting without disturbing the neighbors.

Gemtech’s Mossad suppressor blends gracefully with the lines and proportions of the Uzi because it was designed expressly for this weapon. Its very light weight enables rapid target acquisition. The sophisticated baffle stack delivers plenty of sound suppression and outstanding service life. By selecting the right ammunition, the Mossad can make the open-bolt Uzi quieter than HK’s impressive closed-bolt MP5SD, while delivering a much heavier projectile at a much greater velocity. The Mossad virtually eliminates muzzle flash and climb, and cuts felt recoil in half. This sophisticated suite of outstanding features makes the Uzi an effective and stealthy tool for the modern tactical and sporting environments. I can recommend Gemtech’s Mossad sound suppressor with enthusiasm.

For more information on suppressors, contact Gemtech (Dept. SAR, P.O. Box 140618, Boise, ID 83714-0618; phone 208-939-7222; fax 208-939-7804; URL http://www.gem-tech.com).

By Al Paulson

Only accurate rifles are interesting. Ruger 10/22 and 77/22 rifles are very good values, and they can be customized into very accurate and user friendly rifles with a significant investment of time, effort and expense to make them truly interesting. That said, if you have participated in competition with a fine .22 rimfire target or biathlon rifle, then you must secretly lust after a better rifle to silence. Certainly hunting winter ptarmigan in Alaska at 80-110 yards with an Anschutz Model 54 that would deliver 1/4 MOA with Eley Tenex match ammunition ruined me for life. While the Ruger rifles are ideally suited for suppressing, in my heart of hearts, I’ve long wished that a suppressor manufacturer would introduce a line of suppressed rifles based upon a better rifle. A big part of the problem in my view is that a particular Ruger may or may not be accurate. Unconfirmed reports suggest that Ruger pays between $6 and $7 for a 77/22 barrel. To keep that price, barrels must be made quickly and tool life must be maximized. Therefore, bore and chamber dimensions can be expected to vary. So does accuracy. With careful ammunition selection, one 77/22 will group 3/8 inch at 50 yards, while another will group 3.5 inches- in my experience. Most seem to group around 1.5 inches. There are other compromises that must be made to keep the cost down, which also tend to give the Ruger less gravitas as a serious working tool compared to a fine European target or hunting rifle. I do not fault Ruger for making those choices. I have simply wished someone offered a suppressed rifle based upon a more serious shooting iron. Someone has. Mark White of Sound Technology now offers a suppressed Czech CZ 452-2E ZKM rifle that is worthy of the serious shooter. It is short, handy, robust, very quiet, and—above all—accurate.

Manufactured by Ceska Zbrojovka Uhersky Brod in the Czech Republic, the CZ 452 series of eight different models probably represents the best-selling .22 rimfire rifle design worldwide. Although relatively new to the United States, CZ 452s have been well known and highly regarded elsewhere for a long time. They are noteworthy for their quality, long service life, accuracy, and reasonable price. Their robust design of Mauser heritage features a receiver made from a steel billet, a hammer-forged barrel for accuracy and long life, adjustable trigger, cocking indicator, easy disassembly for routine cleaning and routine maintenance, and a very positive safety at the right rear of the bolt. While this is one of the best .22 rifle safeties I’ve ever seen, I should note that among us sourdoughs in Alaska, it was a solemn if unwritten rule that one never hunted with a round in the chamber. Safeties can fail or be dislodged by brush or a difficult climb up an escarpment. We only chambered a round if we were taking aim on a game animal or if we smelled a bear.

CZ receivers except the “American” models feature an 11 mm dovetail groove for scope attachment. The CZ 452 -2E ZKM model used by Sound Technology is based upon a variant that features the particularly handsome, classic design of a traditional European hunting rifle and the 11 mm dovetail. The CZ features an 18 lpi checkered, beech stock (stained walnut) with Schnabel fore end and beautifully designed and blued European sling attachments that cry out for a simple, soft, fine piece of leather as a carrying sling. The Lux model with stock of Turkish walnut is available for a few extra shekels. I think that would be a good investment, although I’m extremely happy with my beech model thus far. The barrel features an outstanding tangent sight that is adjustable for windage and elevation, with gradations out to 200 meters. It is an excellent sight for young eyes, although mature shooters will be better served by a scope. The tangent sight should really be removed to facilitate scope mounting, especially if the front sight will be removed anyway in the process of making a Silent CZ. In non-U.S. markets, CZ .22 rifles are available with the muzzles threaded to accept sound suppressors. U.S. rifle manufacturers take note. The CZ rifles come standard with 5-round magazines, and both 5- and 10-round spare magazines can be purchased. The barrels have somewhat tighter bores than U.S. standard, about 2 thousandths tighter. The CZ’s firing pin and extractors are far more powerful and robust than the Ruger’s, which are particular weaknesses in the American design. For example, Baikal Junior Steel ammunition may fail to fire in a Ruger, and it generally jams in a Ruger’s chamber and fails to extract. The CZ 452 always fires, extracts and ejects this tough ammunition without a hitch in my experience. All in all, White’s selection of the CZ 452-2E for suppressing was an excellent choice, since it is superior in a host of ways to the Ruger 77/22 and yet it costs about $110 less. How often can you get more for less?

If your primary interest is benchrest shooting, I’d probably opt for White to build his system on one of the American models in the CZ lineup. These feature 3/8 in (12.7 mm) dovetail groove for scope attachment and no iron sights to complicate scope mounting. The American models also feature a broader forestock that is better suited to shooting off sandbags. If you can’t decide which to get, buy one of each. The CZs are inexpensive enough to make that a realistic option. White also builds this design on the Ruger 10/22 for those who favor that rifle.

Table 1 compares the features of the standard CZ 452-2E and Sound Technology’s Silenced CZ rifles. The silenced CZ features White’s latest iteration of his enormously popular M-Can, which is noteworthy for its superb sound reduction, unusual self-cleaning properties, ease of routine maintenance when required, robust construction, extraordinary service life, and—above all—accuracy. This M-Can is 7.38 inches long and 1.25 inches in diameter. The Silenced CZ weighs 6.3 pounds, which is 0.2 pound lighter that the unmodified rifle with beech stock before the conversion. Built like an M1A1 main battle tank, the M-Can is welded to the barrel, so misalignment will never be an issue. This is a one-stamp gun despite the fact that I opted for a 12.4 inch barrel.

It is important to note that even 12.4 inches is longer than White’s preferred embodiment, for a variety of compelling reasons. My logic for the 12.4 inch barrel was both cosmetic and practical. From an aesthetic point of view, a shorter barrel would have required whacking off the front of the forestock, and I didn’t want to lose the graceful Schnabel fore end. Furthermore, a 12.4 inch barrel comes extremely close to providing maximum bullet velocity, enabling me to tailor velocity and terminal ballistics by the selection of ammunition.

White prefers a shorter barrel to ensure that standard velocity target ammunition will stay subsonic under a wide range of environmental conditions. Note that CCI standard velocity and Aguila SE Subsonic have lower velocities than Remington, and so are more suppressor-friendly in this regard. The Aguila solid point subsonic, for example, is very good ammunition and produced an average muzzle velocity of 1,011 fps out of the Suppressed CZ at 95 degrees F (contact Centurion Ordnance, Dept. SAR, 11614 Rainbow Ridge, Helotes, TX 78023; phone 800-545-1542).

A shorter barrel may also be more accurate than a standard barrel, since it may be stiffer and less subject to barrel harmonics. Extensive research into the effect of barrel length versus velocity using a wide variety of ammunition (see Silencer History and Performance, Volume 1, pages 226-235) has clearly demonstrated that the velocity of standard velocity ammunition is at or near maximum with a 12 to 14 inch barrel. By then, no more energy can be transferred from the modest 1 to 1.4 grains of powder combustion gases to the projectile. Friction between the bullet and the bore becomes an increasingly significant factor with longer barrels.

Trigger pull was a consistent if heavy 4.0 pounds, and it exhibited more creep and overtravel than I liked. After several hundred rounds, the creep mellowed out, but trigger pull weight and overtravel remained issues. Sound Tech recently started installing trigger overtravel screws for a modest fee. This modification makes a big difference. Dr. “Nick” Panisuan of Bangkok, Thailand, has developed the definitive methodology for doing trigger jobs on the CZ 452 and an American has documented the procedure, with illustrations, on the Internet. Go to http://projects/chatrifleclub.org/cz452mods.html. Furthermore, at the CZ Forum archives at www.rimfirecentral.com explains how to turn the CZ trigger in to a crisp 8 to 10 ounce trigger pull comparable to a $1000 Anschutz. The CZ Forum also provides a variety of other techniques to improve the CZ’s trigger, as well as a source for replacement springs to facilitate a great trigger job. Bear in mind, however, that this is a particularly nasty trigger to reassemble, so I’d personally hire the work out if you can find a qualified gunsmith. Mark White at Sound Technology will do an excellent trigger job, eliminating overtravel and bringing trigger pull down to 2 pounds, for $55. That’s a mandatory investment in my book.

I evaluated Sound Technology’s Silenced CZ using four kinds of ammunition: Remington high velocity (R HV), CCI Green Tag standard velocity target (CCI SVT) since a superior rifle merits a better target round than Remington’s standard issue, Remington subsonic (R SS), and Russian Baikal Junior Brass subsonic (BJB SS). I used a Ruger 77/22 with 12 inch barrel as the reference standard for unsuppressed performance and a Tasco World Class 6-24x44mm AO scope for accuracy testing, although I eventually replaced it with a much handier Simmons Model 1031 22 MAG 4×28 scope. I was not happy with how the Simmons rings fit the 11 mm dovetail, so I immediately replaced them with Bushnell 76-3022 rings that seem to grip the 11 mm dovetail without a problem, provide just enough clearance for the bolt handle for handy manipulation without being too high for a proper cheek weld, and are much cleaner visually than Simmons or Weaver mounts. CZ offers excellent if expensive steel mounts. Many end-users seem to be particularly happy with mid-priced BLK scope mounts (the same mount works both for 11 mm and 3/8 inch dovetails). BLK mounts can be purchased from Silver Streak Sports; check out their website at silverstreaksports.com/BLK.htm.

I should note that the use of Baikal Junior Steel subsonic (a slightly cheaper alternative to Junior Brass) will quickly kill soft and feeble Ruger firing pins and extractors, but the CZ seems to have no problem with that ammo. I also find it interesting that Eley uses Baikal ammunition for their quality control program when manufacturing Eley premium match ammunition. The fact that the Silenced CZ likes Baikal Junior Steel is particularly gratifying since I’ve got 30,000 rounds of the stuff languishing in storage. The mean (average) sound pressure levels, net sound reductions, and three-round groups (measured center to center) appear in Table 2. The temperature during the testing was 85 degrees Fahrenheit, and the speed of sound was 1,144 fps.

Sound signatures of 112 decibels with standard velocity and subsonic match are nothing short of wonderful. The sound of the striker falling on a CZ 452 is 110 decibels, so Sound Technology’s Silenced CZ is only 2 decibels louder than action noise with the rifle’s most accurate round tested thus far, CCI Green Tag. Note that the muzzle velocities of standard velocity and subsonic rounds are almost identical; clearly a 12 to 12.4 inch barrel is an extremely efficient length. Three 3-round groups averaged 0.18 inch at 50 yards. I haven’t fired such small groups from a .22 rifle in a long time. Wow!

When I grab a silenced bolt-action rimfire rifle these days, it is Sound Technology’s Silenced CZ. It is handsome, affordable, robust, low maintenance, handles and balances to perfection, delivers superb sound reduction (within 2 dB of firing pin noise), and qualifies on the single most important criterion for a silenced rifle in my opinion. It is extraordinarily accurate-nearly three times more accurate than the unmodified CZ 452 rifle when using CCI Green Tag match ammunition. White’s reputation as an accuracy guru is supported by the performance of the Silenced CZ. Furthermore, the Silenced CZ fits my body and my biases to perfection. Only accurate rifles are interesting. The Silenced CZ from Sound Technology is the most interesting suppressed turn-bolt .22 rimfire rifle I’ve yet encountered, and I can recommend it with unbridled enthusiasm.

For more information on the Silenced CZ, contact Sound Technology, Dept. SAR, P.O. Box 391, Pelham, AL 35124 (phone and fax 205-664-5860; URL http://www.soundtechsilencers.com). For information on CZ rifles in general, contact CZ USA, Dept. SAR, 1401 Fairfax TFWY, B-119, Kansas City, KS 66115 (phone 1-800-955-4486; e-mail czusa@gvi.net; website www.cz-usa.com).

By Al Paulson

The integrally silenced Ruger 10/22 is one of the finest semi automatic sporting instruments ever devised. When properly executed, these are very handsome, very quiet, well-balanced rifles that are also capable of excellent accuracy. The state of the art in suppressed .22 rifles and pistols has progressed to a very high level in the last few years, although the Ruger products do vary somewhat in accuracy “Out of the box”. With the proverbial bar set so high, the careful shopper can find performance that was unthinkable just a few years ago. One interesting entry into the highly competitive field of integrally silenced 10/22s is the Phoenix rifle from Advanced Armament Corp. I’ve had the opportunity to evaluate both first-generation and second generation Phoenix rifles, and it’s safe to say that the results were surprising.

Using a similar baffle stack to AAC’s Phoenix pistol, the first-generation Phoenix rifle (henceforth referred to as the Phoenix Type 1) has approximately the same length and weight as an unmodified rifle when the factory stock is inletted to accept the suppressor. The silencer tube is made from 304 stainless steel, which is finished in a matte bead blast finish. The tube completely covers the exposed portion of the barrel. The suppressor has a length of 17.6 inches and a diameter of 0.98 inch. With Simmons .22 MAG 4×32 scope, Weaver rings, Hogue aftermarket stock, and empty magazine, the Phoenix Type 1 rifle evaluated in this study has an LOA of 36.75 inches and a system weight of 6.7 pounds. Since the scope and mounts weigh 12.9 ounces, the Phoenix Type 1 rifle weighs 5.9 pounds without optics. The baffles are CNC machined from 6061-T6 aluminum alloy to minimize weight and to maximize heat transfer from hot combustion gases, which increases the efficiency of the silencer. The 12.5 inch barrel has minimal porting engineered to keep high velocity and standard velocity ammo from generating a loud ballistic crack, while at the same time delivering maximum practicable velocity to provide as much penetration as possible without objectionable bullet flight noise. The porting is designed to give maximum service life for an integral suppressor with ported barrel. It is also worth noting that the rifle is not classified as a Short-Barreled Rifle under BATF regulations, since the suppressor is permanently attached to the barrel.

The Type 2 Phoenix rifle differs from the Type 1 rifle in several important aspects. The most important difference is that the Type 2 suppressor incorporates improved barrel tensioning to reduce barrel harmonics and thereby provide better accuracy. The Type 2 also features a shorter barrel and suppressor tube, measuring 10.5 inches and 15.5 inches, respectively. The Type 2 Phoenix rifle has an LOA of 34.7 inches. It weighs 5.5 pounds without optics, which is 0.4 pound lighter than the Type 1 Phoenix. I very much prefer the handiness of the shorter Type 2 variant. The second-generation Type 2 Phoenix is the variant currently in production.

Taking Stock

Traditional wood, laminated wood, and even fiberglass stocks can be both functional and genuine art. Few things are as maddening as taking a beautiful stock into the field and watching it become dinged, gouged and scarred during the course of active use. There’s something to be said for a rough and tumble stock that sheds abuse that would do violence to a handsome wood or fiberglass stock. While I’m not enamored with the aesthetic appearance of the Hogue OvermoldedTM aftermarket stock for the Ruger 10/22, I am pleased with how it handles during presentation and how it resists scarring from hard use afield.

The Overmolded stock features an internal fiberglass body for solid support combined with a cushioned rubber outer skin for a non-slip grip and a remarkable resistance to dings and gouges. Another variant of the Hogue stock is coated with nylon instead of rubber. The rubber-skinned variant is a robust stock well suited to hard usage (I have no experience with the nylon-skinned variant). The Overmolded stock features a straight comb, wide varmint-style forend, very functional cobblestone finish surfaces on the grip and forestock, dual palm swells on the recurve pistol grip to further enhance comfort and control, a rubber recoil pad, and front and rear sling studs. Fully inletted for a drop-in fit, the Hogue stock is available inletted for factory standard barrels as well as standard aftermarket match barrels with a diameter of 0.920 inch. It is the latter variant with rubber outer skin that Advanced Armament used for the Phoenix Type 1 and Type 2 suppressed rifles evaluated in this study.

No inletting of the stock was performed to make the 0.98 inch suppressor tube fit in the 0.92 inch barrel channel. The inherent flexibility of the stock enables a press fit of the suppressed action into place. This may be the weak link in the system, since the forestock exerts considerable pressure on the suppressor tube throughout its length. My experience with other suppressed carbines is that a free-floating suppressor tube delivers better accuracy than a tube that has any contact with the stock. Testing that hypothesis will be left for another time.

While I much prefer the human engineering of the 1.8 pound Volquartsen thumbhole fiberglass stock for the Ruger 10/22, the 1.9 pound Hogue stock bounced back from the sort of usage that left my Volquartsen stock chipped and scarred. That certainly earned my respect and has made me rethink future stock purchases for Ruger 10/22s that will get hard use in the field.

Performance

I compared the performance of AAC’s Type 1 and Type 2 Phoenix integrally silenced 10/22 rifles with an unsuppressed Ruger 10/22 with factory 18.5 inch barrel, and with AAC’s Cloak silenced Ruger 10/22. The Cloak is actually a Hogue match barrel with a silencer hidden inside. The Cloak silenced barrel fits into aftermarket stocks designed to accept 0.920 match barrels, and it does so without the need for any stock modifications whatsoever. Sound testing was conducted using the specific equipment and testing protocol advocated at the end of Chapter 5 in the book Silencer History and Performance, Volume 1 (Wideworld, Dept. SAR, P.O. Box 1827, Conway, AR 72033; $50 plus $5 s&h, check or MO). Four kinds of .22 LR ammunition were used for the testing: Remington 40 grain high velocity (HV), Remington 40 grain standard velocity target (SVT), Remington 38 grain hollowpoint subsonic (SS), and RWS 40 grain hollowpoint subsonic (SS). Sound and velocity testing of the Phoenix Type 1 and Cloak were conducted at an atmospheric temperature of 84 °F, while accuracy testing was conducted several days later at 88 °F. The Type 2 Phoenix was tested nine moths later at a temperature of 56 °F. Ideally, I would have liked to conduct all sound and all accuracy testing on one day, but this simply wasn’t possible. Ammunition was kept at ambient temperature in a cooler in the shade until needed. Unsuppressed peak sound pressure levels (SPLs) were measured 1 meter to the left of the muzzle, while suppressed levels were measured 1 meter to the left of the suppressor. Reported decibel levels represent the mean (average) of 10 shots.

Velocities were measured using a P.A.C.T. MKIII timer/chronograph with MKV skyscreens set 24.0 inches apart and the start screen 8.0 feet from the muzzle (P.A.C.T., Dept. SAR, P.O. Box 531525, Grand Prairie, TX 75053; phone: 214-641-0049). Velocity data represent a mean value of at least ten shots. The speed of sound was 1,143 fps at 84 °F, 1,157 fps at 88 °F, and 1,113 fps 56 °F. Accuracy testing was conducted at a range of 50 yards using a mechanically buffered cradle-type machine rest that locks the entire rifle in place, with three rounds per group. Reported accuracy data represent the average of three groups. Group sizes represent the center to center distance between the two most widely spaced shots, using custom caliber-specific calipers made by Hunt’s Bullets (Dept. SAR, 6210 Lake Lugano, Jacksonville, FL 32256; phone 904-645-3140).

The peak sound pressure levels (SPLs) of suppressed and unsuppressed rifles are reported in Table 1. Net sound reductions appear in Table 2. Muzzle velocities appear in Table 3. Accuracy data appear in Table 4. As the first table shows, AAC’s Phoenix rifles are generally significantly quieter that AAC’s Cloak rifle. This generalization is easier to see when looking at the net sound reductions shown in Table 2. Table 3 shows that the Cloak must be used with subsonic ammunition to avoid a ballistic crack under these atmospheric conditions with Remington standard velocity, although several folks who own AAC’s Cloak rifles tell me that they have thus far experienced no ballistic cracks using CCI standard velocity ammunition. That said, I always found that the Phoenix could be used with Remington standard velocity ammunition for stealthy shooting. Of course, no rifles evaluated in this study produced objectionable bullet flight noise when used with subsonic ammunition.

All three suppressed rifles give very usable sound reduction with high velocity ammo, since the rifles’ sound signatures will be obscured by the ballistic crack. If several varmints or small game animals are downrange, they will look toward the nearby ballistic crack or the sound of bullet impact—and not the shooter—if proper field craft is employed.

Both Phoenix variants, as well as the Cloak, delivered very stealthy shooting with standard velocity target ammunition. Furthermore, standard velocity ammunition delivered the best accuracy, as shown in Table 4.

Using subsonic ammunition, the Type 2 Phoenix was significantly more accurate than the Type 1 Phoenix, while still delivering outstanding sound reduction with standard velocity and subsonic fodder. Shortening the suppressor and barrel to create the Type 2 Phoenix yielded the same sound reduction as the Type 1 with high velocity and standard velocity ammunition, while the shorter system was only 1 decibel louder when using subsonic ammunition.

To put these sound data in perspective, both Phoenix variants are much quieter than a Crossman American Classic Model 1377 .177 caliber air pistol with any ammunition that does not produce a ballistic crack. Furthermore, even the shorter Type 2 Phoenix delivers sound pressure levels using standard velocity and subsonic ammunition that are within 1-3 dB of action noise (which is 109 dB, measured as the sound of the bolt closing on an empty chamber). Such performance can safely be termed outstanding.

Advanced Armament’s Type 2 Phoenix delivered 0.78 inch groups at 50 yards with standard velocity target ammo, which is significantly better than an unsuppressed rifle. Using high velocity ammunition, neither the suppressed or unsuppressed Rugers with factory barrels shot as accurately. Whether this is because the factory barrels are optimized for standard velocity projectiles or because of tension on the suppressor tube created by the Hogue stock affecting harmonic vibration of the baffle stack remains unclear. Using subsonic ammunition, accuracy wasn’t as good as standard velocity target-grade fodder, which is not uncommon. Still and all, 1.2 to 1.3 inch groups at 50 yards with subsonic ammunition in the Phoenix Type 2 rifle is still plenty accurate to take varmints and small game at that distance with confidence.

It is worth noting that the only suppressed or unsuppressed rifle to provide unmatched accuracy with all categories of ammunition was AAC’s Cloak rifle, with the suppressor hidden inside a Hogue stainless steel match barrel of 0.920 inch diameter.

Several curiosities in the data merit a brief discussion. The Phoenix Type 1 delivered a muzzle signature of 109 dB with Remington subsonic, which was the same level as action noise. The Type 1 produced a sound signature that is a mere 108 dB with RWS subsonic. That’s nothing short of astonishing performance.

How can the overall sound signature of the Phoenix Type 1 possibly be 1 dB quieter than action noise with RWS subsonic? It turns out that the chambering of a live round buffers the ring of the bolt slamming home by about 1 decibel. Using RWS subsonic ammunition, the Phoenix Type 1 delivers the maximum amount of sound suppression that is theoretically usable in a Ruger 10/22, unless measures are taken to further reduce action noise. It is also noteworthy that both the Phoenix and the Cloak suppressors from Advanced Armament are exceptionally good at minimizing first-round pop.

Conclusions

In terms of sound suppression, Advanced Armament’s Phoenix rifle can safely be termed impressive. With the rifle’s most accurate ammunition used in this study—Remington standard velocity target—the Phoenix produced a truly impressive sound signature. Gunshot noise was within a mere 2 decibels of action noise using the Type 1 rifle and within 3 dB of action noise using the Type 2 rifle. Using RWS subsonic ammunition, the Type 1’s sound signature was actually 1 decibel less than the sound of the bolt closing on an empty chamber. It’s hard to imagine squeezing any more stealth out of a silenced 10/22. Using RWS subsonic in the Type 2 rifle, the sound signature was only 1 dB above action noise. From another perspective, that’s 10-13 decibels quieter than a Crossman American Classic Model 1377 .177 caliber air pistol (depending on the number of pumps). When you consider that the decibel scale is logarithmic, it becomes clear that this is very stealthy performance, indeed.

Accuracy of the Phoenix Type 1 rifle was good, but I prefer the accuracy mix delivered by the Phoenix Type 2, even though it’s not quite as accurate with the high velocity and target ammunition used in this study. For those who can utilize even more accuracy, I’d recommend AAC’s Cloak, which delivered 0.45 inch groups at 50 yards with standard velocity target ammunition.

It is interesting to note that AAC’s Cloak—with its silencer hidden inside a match barrel—delivered significantly better accuracy than the Phoenix Type 1 and Type 2 with all categories of ammunition. It is also interesting that the barrel tensioning incorporated into the Type 2 design seemed to work best with subsonic ammunition in the particular rifle I tested.

It is well known that .22 rimfire rifles are notoriously finicky with regard to ammo versus accuracy, and the Phoenix appears to be particularly finicky in this regard. The owner of a Phoenix (or any other suppressed or unsuppressed .22 rimfire) would be well advised to go to a good gunshop and buy a box of every brand and variety of high velocity, standard velocity, and subsonic ammunition that can be found. Spend a day shooting groups from a rest, and find out what delivers the best accuracy from that particular gun. When the best performers are found, try to buy several 5,000 round cases of the same variety (and lot, if possible) of ammunition and earmark that ammo for that particular gun. This extra effort will pay substantial dividends when it comes to accurately placing rounds on target.

That said, simply using Remington standard velocity target ammo in the Advanced Armament’s Phoenix integrally silenced rifle will deliver an extremely stealthy sound signature and much better accuracy than an unmodified Ruger 10/22. That is compelling performance, no matter how you slice it.

The complete Phoenix 10/22 rifle costs $795, while installing the Phoenix on a customer-supplied stainless steel Ruger 10/22 or 77/22 rifle runs $595. AAC can add an outstanding trigger job for $125, including Volquartsen parts. This is highly recommended for the serious shooter. For more information, contact the Advanced Armament Corp. (Dept. SAR, 3100 Five Forks Trickum Road SW, Suite 201, Lilburn, GA 30047; phone 770-985-3109; fax 770-985-3110; website www.advanced-armament.com).

The HEL M2 was an experimental M16 suppressor that used a series of baffles coupled with an expansion chamber extending back over the barrel to the front sight. The M2 model for the M16 rifle was 14 inches long and used 24 baffles forward of the muzzle. Following an ENSURE (Expediting Non-Standard Urgent Requirement for Equipment) request (DA ENSURE Index No. 77) from the USARV (United States Army, Vietnam) for silencers for the M16A1 rifle in May 1966, HEL designed and tested a noise suppressor designated the HEL M4, which was a variant of the M2.

To reduce the bulk and weight of the M2 5.56mm suppressor, HEL shortened the length to 12 inches, reduced the number of baffles, and changed the internal arrangement of components. The number of baffles was reduced from 24 to 11, with the first baffle being positioned backwards (i.e., so that its apex was toward the front of the suppressor). Directly in front of this baffle was a short expansion chamber followed by a baffle positioned normally (i.e., with its apex toward the muzzle of the rifle). This baffle had a very large bullet passage, presumably to reduce back pressure. The next 9 baffles were the same design as the first baffle, but were oriented normally.

The new can eliminated enough of the muzzle blast so that the location of the shooter was undetectable to hostiles downrange, which greatly improved a shooter’s tactical advantage and survivability. Given ideal vegetation and terrain, the muzzle blast from an M16A1 was completely indistinguishable beyond 50 yards. Only the sonic boom created by the 5.56mm projectile remained, which sounds something like the report of a short-barreled .22 rifle. In the absence of a muzzle blast, the mammalian brain interprets the origin of the gunshot as perpendicular to the pressure wave of the ballistic crack striking the body. Combined with the sound of bullet impact, this phenomenon causes individuals to turn their attention 90 to 180 degrees away from the shooter. This is a very good thing during an ambush or when a small force equipped with silencers must cope with a larger force.

To meet the ENSURE #77 requirement, the USARV submitted an acquisition requirement for 1,080 HEL M4 noise suppressors. By December 1967, the first 120 suppressors had been produced, but further production was suspended pending a field evaluation by USARV. Twenty suppressors were sent to USARV for testing.

In March and April 1968, the USAIB (United States Army Infantry Board) tested the M4. The USAIB test found that the M4 had three shortcomings. (1) The gas deflector failed to deflect all of the escaping gases from the firer’s eyes. (2) The ejection pattern of the rifle with noise suppressor attached caused the spent cartridge case to strike the cheek of left-handed shooters. And (3) the malfunction rate of the test rifle was significantly higher than the control rifle during automatic fire. The USAB concluded that the HEL M4 sound suppressor had military potential but it was not the perfect tool for the job, so the Board returned the M4 to HEL for correction of these shortcomings.

Early development at Aberdeen also demonstrated that the M4 generated a number of problems with the M16A1 rifle: (1) increased back pressure; (2) increased cyclic rate; (3) increased rearward bolt velocity, and (4) excessive gas discharge from the ejection port into the shooter’s face. The major problem was the increased back pressure, which actually produced the other problems, such as shearing off the bolt carrier key. HEL solved the bolt velocity and cyclic rate problems by adding an additional gas pressure relief port to the bolt carrier, which enabled reliable functioning of the rifle whether the selector was set to SEMI or AUTO.

The only glitch with this solution was that the rifle would not cycle reliably with the modified bolt carrier unless the suppressor was installed. This meant that a rifle fitted with the modified bolt carrier had to be dedicated for suppressed use only.

Once installed, the suppressor became an integral part of the rifle that could not be removed without swapping the bolt carrier as well. This was not an ideal situation for special operators. Furthermore, the suppressed rifle with modified bolt carrier still dumped a lot of hot combustion gas into the shooter’s face, so HEL added a special gas deflector to the charging handle of the M16A1 rifle. This deflector was not entirely successful, however. In April and May 1968, HEL developed a new, shorter suppressor that eliminated the need for a specially modified bolt carrier. Apart from the removal of 5 baffles from the baffle stack, the new suppressor used the same arrangement forward of the muzzle of the rifle. This new 9.5 inch model was known variously as the HEL M4A, or H4A, or E4A which was its final designation. The gas deflector was also intended to be used with the new suppressor, but there is little evidence to suggest that it was actually used with the E4A suppressors in the field.

Other developers of noise suppressors tried to meet the ENSURE #77 requirement, including SIONICS (a commercial company that eventually merged with the Military Armament Corporation) and Frankford Arsenal (FA; which was a government facility). In May 1968, HEL, SIONICS and FA submitted a total of seven different noise suppressors for testing to meet the ENSURE #77 requirement. The Frankford Arsenal silencers were 1.25 inches in diameter and utilized porous aluminum rather than baffle technology. These very early SIONICS silencers used WerBell’s spiral diffusers, but did not incorporate baffles that would later be seen in his patents and production units. They also featured a flash hider that screwed onto the front end cap of the SIONICS silencer. The HEL M4 and M4A suppressors were tested at Ft. Benning, Georgia, by the USAIB in a Military Potential Test (MPT) against the FA (Frankford Arsenal) FA XM and CM noise suppressors and three different versions of the SIONICS 5.56mm suppressor (the MAW-A1, A2, and A3 models). The test recommendation was that the HEL E4A noise suppressor was suitable for a field evaluation in Vietnam.

The HEL E4A was win-win technology. While it was not as quiet as the M4, it solved all of the reliability and durability issues plaguing the M4 suppressor. Furthermore, it was more compact than the HEL M4. While the E4A did not require a modified bolt carrier (unlike its M4 predecessor), we find it quite interesting that the E4A was considered to be a permanent fixture once it was fitted to a rifle.

The E4A produced a net sound reduction of 26 dB (at 12.5 feet down range and 2 feet to the right of bullet trajectory). That was significantly better than the SIONICS suppressors (by about 10-11 dB), but not as good as the HEL M4 (which produced 35-36 dB reduction) or the FA XM (which produced 32-36 dB reduction). See the accompanying sidebar to learn more about the sound level measurement procedures used for these HEL tests. All of the other five suppressors tested by the USAIB had shortcomings. The performance of the E4A out-shone the other suppressors, especially with regard to the number of malfunctions that occurred during cyclic tests. The malfunction rate of the E4A was significantly lower than all other suppressors tested; during a 1,000-round cyclic rate test, only 3 malfunctions occurred with the E4A.

While some shortcomings were noted with the SIONICS suppressors, SIONICS was well advanced in the use of high-tech materials compared to the other suppressor manufacturers of the time. SIONICS used a plastic bushing under the rear retaining collar. Unfortunately, this bushing melted during a full-auto testing. A redesigned bushing made from Teflon was then submitted during the MPT to rectify this problem. Unfortunately, Teflon melted when temperatures reached about 1,000 degrees F, so SIONICS finally settled upon making the bushings from naval bronze.

Another problem was the gas pressure relief valve. The springs used in the relief valve failed during the cyclic rate testing, so a redesigned spring made from Inconel was submitted in an attempt to rectify this problem. Even resorting to using a high-temperature resistant alloy like Inconel proved unsuccessful, so SIONICS developed its third and final design: a passive gas pressure relief valve with no moving parts. Significantly, the MPT found that the pressure relief valve had no effect on the operation of the test items, and concluded that it was an unnecessary part of the suppressor. It is also interesting to note that use of a gas pressure relief valve with center-fire rifle suppressors has not been seen since its use in the SIONICS suppressors, with one exception. Recently deployed Israeli-made centerfire rifle suppressors for the M16A1 and M14 rifles have featured the use of gas pressure relief valves, despite the fact that advances in internal design have clearly eliminated any need for pressure relief valves.

Two of the SIONICS suppressors used titanium spiral suppressor rings, while the third used aluminum spiral suppressor rings. Following further destruct tests at Ft. Benning, SIONICS made significant changes to the construction and materials used in the 5.56mm suppressors. No internal parts were subsequently made from aluminum, and stainless steel became the material of choice. While the use of titanium has become more widespread in recent years, it is a little-known fact that SIONICS pioneered the usage of titanium in firearms sound suppressors, though undoubtedly the cost factor prevented its widespread use during the Vietnam years. Despite the advances in material use, the SIONICS/MilitaryArmament Corporation’s suppressors were not as widely used as the HEL E4A in Vietnam.

After the MPT report was published in September 1968, final production of the outstanding 960 HEL E4A suppressors was completed, and these were shipped to Vietnam in late 1968 and early 1969 at a cost of $42,000. That works out to less than $46 per unit. According to several sources, the HEL E4A suppressor was used in greater numbers during the Vietnam War than SIONICS/Military Armament Corporation’s suppressors designed for the M16A1 and CAR-15. Rangers, SEALs and Army Special Forces began using HEL M4 silencers in the summer of 1968 and then upgraded to the HEL E4A suppressors, which were employed throughout the remainder of the Vietnam War. The SEALs, however, eventually used a U.S. Navy-developed 5.56mm suppressor rather than the E4A suppressor.

Surprisingly, both the HEL M4 and E4A suppressors were considered to be expendable items. If they were damaged, they were to be destroyed by the company armorer rather than repaired. This may explain why the HEL M4 and E4A suppressors are rarely seen today in collectors’ hands. It is known that during the early 1980s, at least one mail-order company was selling parts kits for the M4, although this practice ceased when ATF changed the definition of a silencer to include silencer parts. If you ever find a transferable M4 silencer, it’s a rare and important historical artifact from the Vietnam War.

By Al Paulson

As unconventional warfare heated up in South Vietnam, former OSS officer and prolific silencer designer Mitchell Livingston WerBell III realized early that a silent carbine of pistol caliber would provide substantial tactical dividends for special and black operations being conducted throughout Indochina. Ideally, the weapon should be similar in size and performance to the impressive .45 ACP Silent Carbine developed by William Godfray De Lisle for Sir Malcolm Campbell of British Combined Operations during World War II. The De Lisle Silent Carbine was used with extraordinary success by British commandos on raids against Fortress Europe prior to D-Day, and against the Japanese in the Indo-Pacific Theater. After VJ Day, the De Lisle carbine proved to be a most useful weapon during the Malaysian Communist Emergency, when it was employed by the British Army and Special Branch Police against Communist insurgents and terrorists in a classic counter-guerrilla warfare campaign. The De Lisle was quiet and powerful, but the baffle stack was fragile and subject to damage in the field, which ruined accuracy. WerBell sought to make a more robust and modern version of the De Lisle that would have all of its virtues and none of its shortcomings. The net result was a series of weapons produced by the Military Armament Corporations that were collectively called the Destroyer Carbine.

The original incarnations of the MAC Destroyer Carbine were based upon the Spanish Model 1921 Destroyer Magazine Rifle. The earliest variants of the Destroyer Rifle were made by Gaztanaga y Compania of Eiber, Spain. Subsequent variants marketed as the Destroyer Magazine Rifle were apparently made in the 1920s and 1930s by Ayra Durex. The Magazine Rifles came in several calibers including 9mm Bergmann-Bayard (also known as the 9mm Largo and 9x23mm), 9mm Parabellum (9x19mm) and .380 ACP (9x17mm). Clearly inspired by the Model 93 Mauser rifle, the Destroyer has a personality all its own. Like the Mauser, the Destroyer cocks upon closing the bolt. The Destroyer also features a Mauser-type wing safety on the bolt sleeve and a Mauser-like claw extractor. Unlike the Mauser, however, the extractor is located on top of the bolt rather than on the right side. Furthermore, the bolt’s two locking lugs are located just in front of the bolt handle, perhaps half of the way back from the bolt face. This arrangement is reminiscent of a Ruger 77/22 rather than a Mauser M93 and facilitates the stripping of rounds from a pistol magazine.

For several reasons, WerBell decided to chamber his modern incarnation of the De Lisle Silent Carbine for the 9x19mm cartridge rather than the De Lisle’s more potent .45 ACP, despite the fact that M1911 magazines fit neatly in the magazine well of 9x23mm Destroyers. Doing so saved expensive re-manufacturing and heat-treating of the bolt. Furthermore, the steel used in the Model 1921 rifles was very soft and of variable quality, so there was some question whether the actions could stand up to the larger cartridge when used for military-rather than sporting—applications.

WerBell developed a number of variations on the 9mm Destroyer theme. Some contained replaceable wipe modules, while others were based on WerBell’s typical frusto-conical baffles.

WerBell developed at least five documented variants of the Destroyer Carbine. One variant used a shortened barrel with an early suppressor designed for the Ingram M10 9mm submachine gun. This early suppressor featured a single tube measuring approximately 1.75 inches in diameter and 10 inches in length.

Another variant used the standard MAC .30 caliber suppressor designed for the M14 rifle. The bore of the M14SS-1 silencer was sufficiently large to safely accommodate the relatively short 9mm pistol projectile. This variant was particularly accurate when fitted with a Tasco 4-power scope, but it was not particularly quiet—even with subsonic ammunition, delivering a sound signature of 136 decibels when I test-fired this Destroyer with Black Hills 147 grain RN FMJ subsonic ammunition. (That’s comparable to the sound signature of HK’s UMP-45 submachine gun with B&T’s SD UMP silencer.) A photo of this variant of the MAC Destroyer with M14SS-1 silencer accompanies this discussion.

A third variant employed a two-stage suppressor that featured a replaceable wipe module called an “auxiliary front chamber” at the front end of the can. The entire two-stage suppressor measured approximately 1.5 inches in diameter for its entire length, which was about 11.75 inches. The rear end of the can extended back to the Destroyer’s receiver.

A fourth variant was identical to the third, except the wooden butt stock was removed and the weapon was retrofitted with a collapsible wire stock and pistol grip, along with a side-mounted Mossberg 4-power .22 rimfire scope. This version was demonstrated at the ARVN Infantry School in South Vietnam in the late 1960s. The Army ordered a small quantity (4 to 10) of improvised silenced carbines for field evaluation in Vietnam in 1969. It is not clear which of the preceding variants was used to fill that requirement.

The final variant featured a simple suppressor measuring about 1.5 by 11 inches that came back to within 1/4 inch of the receiver. It was this variant that was delivered to the Army in some quantity, when an order for carbines was placed with the Military Armament Corporation.

The second Army order arrived just as the availability of the Spanish rifle dried up in the States. Therefore, most of the Destroyers delivered to the Army were built upon the Remington 788 rifle, which was converted to 9mm and modified to accept modified Walther P-38 pistol magazines and a Tasco 4-power scope mounted directly on the receiver. I have not yet learned how many Destroyers were actually delivered to the Army.