Testing & Evaluation: V1N1

By Al Paulson

1997 Silencer Trials

Dateline: Knob Creek, KY, May 22, 1997. This day was an unprecedented event in the annals of small-arms history; almost all of the silencer manufacturers in the United States came together to have the performance of their sound suppressors tested side by side, using scientifically appropriate sound test equipment. This was very much a team effort with me supervising the tests, Dr. Phil Dater handling the Larson Davis Model 800-B sound meter with Larson Davis 2530-1133 1/4 inch random incidence microphone and automated data recording using a Hewlett-Packard OB-425 computer and software he developed for the purpose, and Dan Shea organizing the scheduling, volunteer shooters and the ammunition supply. We also used a Pact MK-IV Timer/Chronograph with MK-V skyscreens for recording projectile velocities.

I figured we had time to run 60 tests that day, but the demand for data was so intense that we somehow managed to squeeze in 163 test strings. We gathered as much data in a day as I normally produce in a year, giving all of the participants a chance to see how their products measured up to the competition in terms of hard numbers and subjective qualities such as tonality.

It’s hard to adequately express, much less overstate, my admiration for all of the participants since the complete spectrum of the industry was represented. Relatively new, one-man operations competed against well-established design teams of more well-known companies like Knight’s Armament and Gemtech, all competing on a level playing field. Some participants were pleasantly surprised by the performance of their products, while some discovered that individual products needed some refinement.

Several manufacturers expressed displeasure that a particular model did provide nearly as much sound reduction, looking at an average of ten shots, as a similar model of a competitor. Yet that louder model might be an integrally suppressed .22 pistol that delivers more velocity, which is important for anyone shooting a live target instead of punching paper or pop cans. Another suppressor might be louder than a competing model, but it’s half the price of the ultraquiet competitor, or significantly shorter or lighter or more durable. The sound moderator from one manufacturer comes to mind as an example; it is small, light and durable while providing significantly less sound reduction than the manufacturer’s own and competing full-sized suppressors. But the compact size is especially valuable when fitted to an entry weapon, and the moderator will enhance command and control while protecting the operator from short-term and long-term hearing loss. A silencer or moderator that is relatively loud may still be an appropriate tool for a given set of circumstances.

There are more subjective considerations as well. For example, a somewhat louder suppressor or integrally suppressed firearm with superb craftsmanship and cosmetics might make a more handsome and appropriate family heirloom. Sometimes maximum sound suppression is, indeed, the single most important design or performance criterion when selecting a suppressor for a particular application, but sometimes it’s well down on the list of priorities. Here’s a list of design and performance criteria that should be used when evaluating suppressors. How these criteria are ranked in terms of priority will vary with each and every end-user’s circumstances and requirements.

Criteria for Suppressor Selection

1. length
2. diameter
3. weight
4. materials
5. durability of construction (operational lifespan)
6. tonality of sound signature (dominant frequency or pitch)
7. sound pressure level of sound signature (or net sound reduction)
8. first-round pop
9. wet or dry technology?
10. effect on projectile velocity
11. effect on accuracy
12. handiness (human engineering)
13. cost
14. appearance
15. maintenance requirements
16. mounting system
17. type of finish
18. reputation of manufacturer
19. time to drain if full of water (relevant for some SpecOps requirements)
20. time to mount and dismount from weapon (relevant for some SpecOps requirements)
21. quality control
22. ability to deliver required quantities within any time constraints

The learning process at the suppressor trials was by no means limited to the sound testing and discussions on design and performance criteria. Throughout the very long day, the various manufacturers chatted with each other, discussing the fine points of suppressor design, such as how a designer was trying to manipulate gas flow with a new baffle design, problems trying to reduce first-round pop, or the use of exotic materials and fabrication techniques. Suppressor designers frequently offered suggestions to a competitor on how to solve a particular problem. That is not to say that folks swapped their most valuable proprietary knowledge, but they shared information of a depth and quality that I found both remarkable and heartwarming. I know of no other small, highly competitive industry where the principals are so gracious and genuinely helpful to their competitors. Mark White of Sound Technology added to this sense of community by throwing a barbecue for all of the participants at the end of the day.

While space constraints preclude reporting the data here, it is appropriate to highlight a sampling of products that impressed me. Ralph Seifert of R.A.S.E., for example, has developed an innovative baffle design for the .22 rimfire that provided impressive performance in his Labyrinth (an integrally suppressed Ruger 10/22 rifle) and Photon (an integrally suppressed Mountain Eagle pistol). The Photon is remarkably light since it uses a largely plastic pistol plus an innovative carbon fiber suppressor tube. The Photon also features a reinforced barrel which may well eliminate the durability problems often associated with earlier attempts to suppress this pistol by other manufacturers.

Don Austin Wagenknecht brought a particularly diverse product line, ranging from a suppressed cane gun, to an efficient suppressor for the Cobray M11/9 submachine gun, to an ingenious muzzle can for the S&W Model 422 pistol.

While John’s Guns suppressed Marlin Camp Carbines provided good performance in a handy package, the integrally suppressed Ruger 22/45 pistol and Ruger 10/22 rifle designed by John Tibbetts were particular crowd pleasers. His suppressed Ruger Mark II was the quietest integrally suppressed Ruger pistol of the day, beating such industry benchmarks as the outstanding Operator from Gemtech and revolutionary Amphibian from AWC Systems Technology. His Ruger 10/22 was also one of the quietest of the intergrally suppressed 10/22s evaluated during the trials.

Mark White introduced one of the most popular designs of the day—as evidenced by the crowd of dealers wanting to test fire the system during the picnic following the trials—with his Dark Star suppressor mounted on a Ruger Model 96 lever-action rifle firing 260 and 325 grain subsonic .44 Special loads. Originally developed for 7.62x51mm sniper rifles, this superb suppressor made the .44 rifle quieter than a factory original H&K MP5 SD while delivering far superior terminal ballistics. The crowd waiting to fire the suppressed .44 only dispersed when White finally ran out of ammunition.

Jonathan Arthur Ciener, who is the oklest continuously operating suppressor manufacturer in the United States (and one of the oldest in the entire world), had such a confidence in his earliest work that he brought original prototypes from the 1970’s for testing. Even though these designs are several decadesold , I was most impressed by their durability, outstanding workmanship, and the fact that they still provided solid sound reduction compared to the very latest generations of suppressors brought by other. Perhaps the best way to put Ciener’s work in perspective is to note that he was the first to design an effective suppressor for the UZI submachine gun. The salient point is that Ciener developed that UZI suppressor soon after a team of scientist working for Uncle Sam had concluded that it was theoretically impossible to design an effective and practical suppressor for the Uzi, after the goverment had thrown cubic dollars and numerous engineers at the project. It is safe to say that Jonathan Arthur Ciener has played a piotal role in the development of silencer technology as well as in the popularization of that technology with American civilians. The entire industry owes him a considerable debt of gratitude for his contributions.

SIOPTS provided a titanium suppressor with quick-mount system that fastens directly to an unmodified M16A2 or M4 flash hider, something that no one else has accomplished to my knowledge. Furthermore, SIOPTS developed a very heavy, frangible tungsten subsonic round that actually cycles the action—another “impossible dream” that has become reality. While the round provided disappointing accuracy during the trials, it turned out that a loose flash hider on the rifle was the culprit. Subsequent testing demonstrated that the round is capable of delivering a head shot at 100 yards, as long as a barrel with a 1 in 7 rate of twist is used.

Joe Gaddini of SWR was the only manufacturer to bring suppressors for the .40 S&W variant of the MP5 submachine gun, offering a compact sound moderator, a medium-sized suppressor, and a full-sized suppressor. A former engineer at Knight’s Armament Company, Gaddini takes great pains not to infringe upon the proprietary designs of KAC, which is something I greatly admire. His design strategy is to minimize first-round pop at the expense of the average sound pressure level, based on the premise that—for serious applications—the sound signature of the first shot is most critical. While his .45 caliber suppressor for the H&K Mark 23 pistol is louder than the KAC SOCOM suppressor, for example, the amount of first-round pop is less.

That said, the performance of the SOCOM suppressor designed by Doug Olson and Reed Knight was most impressive, producing a sound signature that was less than many suppressed .22 rimfire rifles and pistols. As impressive as the sound signature was, I was even more impressed by the suppressor’s overall design in terms of baffle configuration, fabrication, metallurgy, durability, and finish. Just the tooling to manufacture the complex fluted baffles cost several hundred thousand dollars, and a robot performed all of the complex welding to provide excellent quality control. The Nielsen device in the rear of the suppressor that enables the pistol to cycle reliably—together with the ability to easily zero the point of impact when mounting the suppressor on any pistol—represent remarkably sophisticated engineering. While the Mark 23 pistol with Knight suppressor is a large and heavy package on paper, the reality of handling this system is quite different than mere statistics suggest. Balance and handling are superb, making it easy to deliver rapid double taps at 50 yards. The pistol’s sound signature is significantly quieter than an MP5 SD integrally silenced submachine gun, and it delivers vastly superior terminal ballistics. The H&K Mark 23 pistol and Knight suppressor together form a new and impressive state of the art.

Gemtech fielded a new 9mm pistol suppressor called the Vortex-9, which provided a remarkable 28 dB reduction when fired dry on a Beretta 92F pistol and 35 dB after a half teaspoon of water was poured into the back of the suppressor and allowed to seep through ported baffles into structures that trap the water so it doesn’t leak from a holstered suppressor. The Vortex-9 did not smoke or spatter the operator with droplets of greasy grime, and the impressive performance when wet seems to last for two magazines-worth of shooting. While Gemtech’s M4-96D quick-mount suppressor for the M4 carbine normally equals or slightly outperforms the KAC M4-QD with M855 ball ammo, the Knight suppressor dramatically outperformed the Gemtech suppressor with Winchester USA (so-called White Box) 55 grain fodder. While most suppressors perform very well with Winchester USA pistol ammunition, we learned during the course of the trials that many suppressors do not perform as well as expected when employed with Winchester USA ammo of rifle caliber. Winchester has just discontinued the production of rifle caliber paramilitary ammunition, so this phenomenon can be relegated to a point of historic interest.

John Weaver of JRW fielded a diverse array of suppressors, from an impressive integrally suppressed Ruger 10/22 rifle to a suppressed Sako rifle in .300 Whisper that was quieter than an H&K MP5 SD. JRW’s OTB 22 muzzle can provided excellent performance shot dry on a Marlin 39A rifle and wet on a Walther PP pistol.

The integrally suppressed firearms made by Curtis Higgins of S&H Arms of Oklahoma provide an almost ideal maximum projectile velocity without sacrificing sound reduction. In fact, the

S&H suppressed 10/22 rifle was significantly quieter than most silenced 10/22s I’ve tested. The impressive R.A.S.E. 10/22 beat the performance of the S&H gun by 1 decibel but delivered 43 fps less velocity. I’ve tested some 10/22s that delivered nearly 200 fps less velocity without being nearly as quiet as the S&H gun. It is interesting, however, that one of my favorite .22 pistols of the day was also one of the loudest of its type. Higgins developed an exquisitely handsome suppressed High Standard pistol that is 12 decibels louder than his standard suppressed Ruger Mark II pistol, and the silenced High Standard also has a substantial first-round pop. But it uses a suppressor tube that has a diameter of just 7/8 inch, which enables Higgins to make a package of extraordinary aesthetic appeal. Finally, I can’t go on without mentioning the S&H clone of the H&K MP5 SD, which delivered substantially better sound reduction and substantially higher projectile velocity with both supersonic and subsonic ammunition than a factory original MP5 SD. That’s a most impressive engineering achievement.

Dale Summers of Summers Machine Enterprises produces integrally suppressed Ruger rifles and pistols that give a good mix of sound reduction and projectile velocity, while delivering much better than average accuracy. Summers has a small but fiercely loyal following of regular customers, one of whom provided the pistol for testing. The Spec Op’s Shop provided an interesting array of titanium suppressors for the Ruger 22/45 pistol, Beretta 92F pistol, MP5 submachine gun, Remington PSS rifle, and Colt M4 carbine. The Spec Op’s Shop 9 inch variant of the 5.56mm Viper outperformed the very successful HRT from AWC Systems Technology.

Finally, we tested the subsonic 5.56x45mm White Tip ammunition developed by Whit Engel of Engel Ballistic Research. Using an aftermarket M4 clone and a Gemtech M4-96D suppressor, we tested two variants of subsonic ammunition: one features a 55 grain projectile, while the other uses a 69 grain projectile. The suppressed sound signatures were 117 and 118 decibels, respectively, which is quieter than many suppressed .22 rimfire rifles and pistols. Using a barrel with a twist of 1 in 9, these subsonic rounds provide the capability to deliver head shots at 80 yards.

My thanks to all of the suppressor manufacturers and volunteers who made the 1997 Silencer Trials a success. Forthcoming issues of Small Arms Review will provide a more detailed examination of sound suppressor technology from each of the participants in the 1997 Silencer Trials. We hope to make this an annual event which will draw participants from throughout the United States and overseas as well. The trials provided a great learning experience for all of the manufacturers, volunteers, and dealers who participated in the event.

Participating Manufacturers

Don Austin Wagenknecht
12400 Blue Ridge Blvd.
Grandview, MO 64030

Engel Ballistic Research
Rt. 2, Box 177C
Smithville, TX 78957

Gemtech
P.O. Box 3538
Boise, ID 83703

John’s Guns
3010A Hwy. 155 N.
Palestine, TX 75801

Jonathan Arthur Ciener, Inc.
8700 Commerce Street
Cape Canaveral, FL 32920

JRW
3425 Yule Tree
Edgewater, FL 32141

Knight’s Armament Co.
7750 9th Street SW
Vero Beach, FL 32968

R.A.S.E.
P.O. Box 866
Cocoa, FL 32926

S&H Arms of Oklahoma
P.O. Box 121
Owasso, OK 74055

SIOPTS
570 A Industrial Park Dr.
Newport News, VA 23608

Sound Technology
P.O. Box 391
Pelham, AL 35124