Thor Raider

The THOR Raider represents a durable, compact and ultra-quiet suppressor for 5.56mm caliber firearms. The Raider is so effective Thor says it can be used safely and comfortably without hearing protection in confined areas. It is designed to be run on bolt rifles and

semi-auto AR platforms. This suppressor is an extremely strong and lightweight unit, constructed of 100% titanium.

• Caliber: 5.56
• Length: 6.7 in.
• Diameter: 1.560 in.
• Weight: 15.8 oz.
• Factory-Tested Sound Reduction: 25-35% (Depending on Ammunition)
• Materials: Titanium
• Finish: Black, Olive Drab, FDE
• MSRP: $715
• awcsilencers.com

AWC Silencers

Thor ThunderTrap

The AWC Silencers THOR Thundertrap is a shorter, lighter, and astonishingly quiet suppressor that celebrates the 5th generation of the Thundertrap. Delivering accuracy demanded by law enforcement snipers, the Thundertrap retains spent gases for a longer period causing the sound emitted to be a soft hiss rather than a pop. It is constructed for all centerfire, bolt and semi-auto rifles.

• Caliber: 5.56 | 6.5 | .308 | .338
• Length: 8.125 in.
• Diameter: 1.640 in.
• Weight: 1 lb. 3 oz.
• Factory-Tested Sound Reduction: 35-45%
• Finish: Black, Olive Drab, FDE
• MSRP: $815
• awcsilencers.com

Barrett Firearms

AM 338

Made of a lightweight, high strength Titanium alloy, which is 100% CNC machined and orbital welded to minimize weight without sacrificing durability. The AM suppressors are designed to quickly attach to a recoil-reducing Barrett muzzle brake, which offers high decibel reduction and other key factors such as accuracy, repeatable point of impact shift, and flash reduction—even in low light environments.

• Caliber: 338 and less
• Length: 9.9 in.
• Diameter: 1.8 in.
• Weight: 1.3 lbs
• Factory-Tested Sound Reduction: -23-28 dB
• Materials: Titanium Alloy
• Finish: Black
• MSRP: $1,530
• barrett.net

Barrett Firearms

QDL

Specifically engineered for the M107A1, Model 99, and Model 95, the QDL suppressor attaches to the rifle via proprietary recoil reducing muzzle brake while maintaining 100% function and reliability. The baffle stack features redundant 360-degree CNC welds to contain extreme pressures, while the suppressor’s dual-layered tube is constructed of high strength alloys to ensure both durability and safety in any condition.

• Caliber: 50 BMG
• Length: 14.8 in.
• Diameter: 2.5 in.
• Weight: 4.9 lbs
• Factory-Tested Sound Reduction: 23 dB
• Materials: 4130 Steel
• Finish: Black and Flat Dark Earth
• MSRP: $2,978
• barrett.net

B&T AG – Switzerland

RBS QDN SD-122812

Gas in the face may present health risks to the shooter. This issue was first addressed in 2013 when B&T produced a suppressor designed for the B&T MP9 machine pistol. The RBS suppressor significantly reduces the amount of gas exhausted from the ejection port. The RBS combine the following qualities: significant reduction of gas, minimal impact on rate of fire, similar flash reduction as a conventional suppressor, similar sound reduction as a conventional suppressor.

• Caliber: 5.56, .223
• Length: 6.6 in.
• Diameter: 1.9 in.
• Weight: 23.1 oz.
• Factory-Tested Sound Reduction: 22dB
• Materials: Inconel / Thermax
• Finish: Sandblasted
• MSRP: $1145
• Bt-ag.ch

B&T AG – Switzerland

RBS SQD SD-988206

The B&T RBS SQD – Reduced Back Pressure Suppressor is another member of the B&T family of suppressors that dramatically reduces the amount of gas directed at the face of the shooter. The rock-solid, 3-lug attaching system mounts the suppressor bayonet-style in one quick motion. To remove the suppressor, the operator only needs to press one lever and pull in the opposite direction. This ingenious system will not become loose even while firing full automatic.

• Caliber: 9mm
• Length: 7.6 in.
• Diameter: 1.6 in.
• Weight: 13.9 oz.
• Factory-Tested Sound Reduction: 30dB Reduction
• Materials: Aerospace Aluminum Alloy
• Finish: Anodized
• MSRP: $750
• Bt-ag.ch

Elite Iron

Asset

The new patented ASSET .30 caliber suppressor is all modular in design. Titanium, aluminum and 4140 heat treat construction gives the ASSET a rugged yet lightweight feel. It weighs in at 23.5 ounces, fully assembled, and with a brake. Removing the second stage, the weight is 16.5 ounces. Interchangeable butt sections allow for use on a multitude of different rifles from .223 to .300 WinMag. A true ASSET for every type of marksman and every shooting application. 

• Caliber: .30 Cal
• Length: 10.2 in.
• Diameter: 1.6 in.
• Weight: 23.5 oz.
• Factory-Tested Sound Reduction: Preliminary testing 27-30 dB (depending on caliber)
• Materials: Titanium, 7075 Aluminum and 4140 Heat treat
• Finish: Blasted
• MSRP: $1500
• eliteiron.com

Griffin Armament

Bushwhacker 46

The Bushwhacker 46 was designed to exceed end user desires for the best large bore (.46 caliber) universal suppressor on the market.

Engineered to be more compact, more durable, with higher performance, and more mounting options than any other, Griffin bills the Bushwhacker 46 as the class leader in the universal suppressor category. 100% user serviceability allows owners to completely take apart, clean, and maintain their suppressor to extend its life for years to come.

• Caliber: rifle calibers from .22 up to 45-70 Govt, Pistol calibers up to .45 ACP
• Length: 7.75 in.
• Diameter: 1.5 in.
• Weight: 15.8 oz-17.6 oz.
• Factory-Tested Sound Reduction: 30.8db .223 REM, 28.7db .450 BUSH, 33.6db .300 BLK
• Materials: H900 17-4 Stainless Steel
• Finish: Black Nitride
• MSRP: $999
• griffinarmament.com

Griffin Armament

Optimus 9

Years ago Griffin Armament introduced a market-changing product, the Optimus suppressor. This suppressor could be used on both a handgun, as well as a rifle, was modular for length, modular for mounting system, and was also user serviceable. The Optimus 9 provides multi-tool functionality with premium materials, workmanship, and application of technology. For end users looking for a universal suppressor that covers 90% of popular commercial cartridges, consider the Optimus 9 suppressor.

• Caliber: rifle calibers .22 Cal up to .300 Win Mag, Pistol calibers up to 9mm
• Length: 7.9 in. full configuration, 6.6 in. short configuration
• Diameter: 1.375 in.
• Weight: 15.7 oz. full configuration, 12 oz. short configuration
• Factory-Tested Sound Reduction: 20db 9mm, 32db .308 WIN
• Materials: H900 17-4 Stainless Steel
• Finish: Black Nitride
• MSRP (USD): $1,095
• griffinarmament.com

KGM Technologies

R556-QD

KGM Technologies’ R556-QD is a mission-driven, hard-use rifle suppressor. The R556-QD was developed for use on short barreled select-fire M4 weapon systems. By reducing sound, flash and recoil the R556-QD gives the operator a total signature reduction advantage. Featuring the KGM’s APEC Technology, the massive reduction in back pressure means reduced exposure to harmful gas particulates.

• Caliber: 5.56 NATO Full Auto Rated
• Length: 5.7 in.
• Diameter: 1.5 in.
• Weight: 14.7 oz.
• Factory-Tested Sound Reduction: 25+DB Reduction
• Materials: Inconel & Stainless Steal
• Finish: Cerakote
• MSRP: $850
• Kgm-tech.com

KGM Technologies

R30

KGM Technologies’ R30 is a titanium precision rifle suppressor. Coming in at an impressive size and weight for its caliber class, the R30 can handle any centerfire rifle caliber up to 300 Norma Magnum and 300 PRC. Featuring KGM’s APEC (Adjustable Port End Cap) technology, the end user can tune the systems recoil impulse to their personalized liking. A secondary benefit of the APEC is a reduction in back pressure on semi-auto rifle systems.

• Caliber: 30 Cal
• Length: 7.3 in.
• Diameter: 1.75 in.
• Weight: 10.1 oz.
• Factory-Tested Sound Reduction: 25+DB Reduction
• Materials: Grade 9 & Grade 5 Titanium
• Finish: Cerakote
• MSRP: $1,000
• Kgm-tech.com

SIG SAUER

SLX Suppressors

The SLX series of rifle suppressors feature the new Clutch-LOK QD mounting system which is easy to use, repeatable, and extremely durable. The internal multi-flow path within the SLX suppressors results in 70-80% less toxic gasses blowing back into the shooter’s face. The SLX series is a performance-based suppressor designed for use with supersonic ammunition and ideal for users focused on flash reduction and lower toxic fumes with excellent signature reduction.

• Caliber: 7.62, 5.56
• Length: 5.2 in. to 7.4 in.
• Diameter: 1.67 in.
• Weight: 12.6 oz. to 19.4 oz.
• Factory-Tested Sound Reduction:
• Materials: Inconel
• Finish: Cerakote
• MSRP: $1050
• sigsauer.com

SIG SAUER

SLH Suppressors

The SLH series of rifle suppressors also features the new Clutch-LOK QD mounting system, and an internal multi-flow path with a focus on sound reduction, while also reducing up to 50% of the toxic fumes venting through the ejection port. The SLH is optimized for sound reduction and is ideal for users that use both supersonic and subsonic ammunition.

• Caliber: 7.62, 300BLK
• Length: 7.4 in. to 8.8 in.
• Diameter: 1.67 in.
• Weight: 8.8 oz. to 21.1 oz.
• Factory-Tested Sound Reduction:
• Materials: Inconel or Titanium
• Finish: Cerakote
• MSRP: $1050
• sigsauer.com

SRT Arms

Integrally suppressed Ruger MkIV

An SRT Arms integral suppressor assures hi-velocity ammo will run at subsonic speeds and is shorter and quieter than any muzzle-attached suppressor using similar ammunition. Accuracy is typically enhanced over the factory barrel as we use a tensioned barrel suppressor design. This integral suppressor is removable from the gun for service. NOTE: Customer must supply host pistol for conversion.

• Caliber: .22
• Length: 7.1 in.
• Diameter: 1 in.
• Weight: 34 oz.
• Factory-Tested Sound Reduction: 111-116 db absolute SPL depending on ammunition.
• Materials: Inconel or Titanium
• Finish: Bead blasted stainless, blue, or tan Cerakote finish
• MSRP: $725-$995
• srtarms.com

TacSol / Tactical Solutions

AERIS Micro Rimfire Suppressor

At 3.0 ounces and 3 inches in length, the Tactical Solutions’ AERIS is an economical multi-caliber, lightweight, user-serviceable, and compact suppressor.  It is constructed with titanium baffles and is the perfect platform for .22 long rifle, .17HM2, .17HMR, .17WSM, and .22WMR calibers. The AERIS has a 1-inch outside diameter, which compliments most barrel profiles, and can be threaded on any ½ x 28 threaded muzzle.

• Caliber: .22LR, .17HM2, .22WMR, .17HMR, & .17WSM
• Length: 3 in.
• Diameter: 1 in.
• Weight: 3 oz.
• Factory-Tested Sound Reduction: Pistol: 134.64 dB – Rifle:  118.02 dB
• Materials: Aluminum, Titanium, Stainless Steel
• Finish: Anodized Matte Black
• MSRP: $297
• tacticalsol.com

TacSol / Tactical Solutions

X-RING Takedown TSS Barrel

The X-RING TAKEDOWN TSS is an extremely quiet integrally suppressed barrel for the Ruger 10/22-style takedown receiver and the TacSol X-RING takedown receiver, which also includes takedown connecting hardware. At only 16.9 ounces the X-RING TAKEDOWN TSS barrel features a lightweight, accurate, and durable aluminum barrel, titanium sound suppression baffles, and stainless steel split tube for quick and easy cleaning.

• Caliber: .22 Long Rifle
• Length: Bore Length: 12.9 in. [ 16.75 in. overall ]
• Diameter: .920 in. / 1.00 in. at the muzzle
• Weight: 16.9 oz
• Factory-Tested Sound Reduction: 112.2 dB
• Materials: Aluminum, Titanium, Stainless Steel
• Finish: Anodized Matte Black
• MSRP: $635
• tacticalsol.com

Thunder Beast Arms Corp

Dominus-SR

The Dominus-SR is a true light-weight “go to war” suppressor and is perfect for 5.56 assault rifles and .30 caliber battle rifles, including SBR and full-auto variants. It retains the accuracy and repeatability TBAC is known for. It’s equally at home on a 0.25 MOA bolt rifle on the 1500-yard range as it is on a MK18 in the CQB house. Note that Thunder Beast does not list sound reduction in the spec chart below and instead lists the measured sound level because the unsuppressed starting point changes based on muzzle device used.

• Caliber: Up to .30 (.223 & 5.56 included)
• Length: 6.95 in.
• Diameter: 1.80 in.
• Weight: 12.5 oz.
• Factory-Tested Impulse Level: B&K PULSE data: 137 dB (milspec left/right) and 126 dB at shooters-ear on a 20-inch .308 
• Materials: Grade 5 titanium
• Finish: High temp Cerakote
• MSRP: $1495 (includes one mount)
• thunderbeastarms.com

Thunder Beast Arms Corp

338 ULTRA SR

The 338 ULTRA SR is TBAC’s high-performance .338 caliber suppressor. It offers class leading suppression levels for big magnums like .300 Norma and .338 Lapua Magnum, a light weight design, and our “SR” quick attach/detach mount that offers locking secondary retention in addition to absolute return to zero.  It was Accuracy International’s choice for the ASR submission rifle. Note that Thunder Beast does not list sound reduction in the spec chart below and instead lists the measured sound level because the unsuppressed starting point changes based on muzzle device used.

• Caliber: up to .338 cal
• Length: 11.0 in.
• Diameter: 1.775 in.
• Weight: 20.2 oz.
• Factory-Tested Sound Reduction: B&K PULSE data with .338 Lapua Magnum 135-138 dB at the muzzle, and 124-128 dB at the shooter’s ear
• Materials: Grade 5 titanium
• Finish: High temp Cerakote
• MSRP: $2195 (includes one mount)
• thunderbeastarms.com

Yankee Hill Machine

Phantom .22

The Phantom .22 provides superior sound reduction thanks to a newly designed baffle system. Features include a shielded, interlocking baffle stack made from heat-treated 17-4 stainless steel, a two-part outer assembly with an aluminum blast chamber, and a tube which houses the baffle stack. The rear of the blast chamber serves as the takedown tool for the muzzle cap. The Phantom .22 can handle rounds up to 5.7x28mm while only weighing four ounces.

• Caliber: 17HMR-5.7×28
• Length: 5.5 in.
• Diameter: 1.1 in.
• Weight: 4 oz.
• Factory-Tested Sound Reduction: 114 dB (9mm 4.25” barrel)
• Materials: Aluminum & Stainless Steel
• Finish: Hardcoat Anodized
• MSRP: $388
• YHM.net

Yankee Hill Machine

R9 9mm

When YHM set out to make the R9, the goal was a 9mm suppressor capable of handling high volumes of fire while able to run other calibers such as .300 BLK and .308 Win. Primarily focused on suppressing 9mm (specifically submachine guns and SBRs,) it was made at a budget-friendly price while maintaining the durability one expects from YHM. The R9 is capable of being used on a handgun in conjunction with our Nielsen booster assembly.

• Caliber: 17HMR-9mm /.308 Win
• Length: 5.2 in.
• Diameter: 1.562 in.
• Weight: 10.7 oz.
• Factory-Tested Sound Reduction: 123 dB (9mm 4.25” barrel)
• Materials: 17-4 Ph Stainless Steel
• Finish: Matte Black Cerakote
• MSRP: $494
• YHM.net

THOR THUNDERTRAP

The AWC Silencers THOR Thundertrap is a shorter, lighter, and astonishingly quiet suppressor that celebrates the 5th generation of the Thundertrap. Delivering accuracy demands by law enforcement snipers, the THOR Thundertrap retains spent gases for a longer period causing the sound emitted to be a soft hiss rather than a pop. It is constructed for all center fire, bolt and semi-auto rifles.

• Caliber 5.56 | 6.5 | .308 | .338
• Length 8.3in
• Diameter 1.640in
• Weight 22 oz
• Factory-Tested Sound Reduction 32
• Materials TITANIUM
• Finish BLACK, OLIVE DRAB, FDE
• MSRP (USD) $815
• awcsilencers.com

AWC SILENCERS

THOR TURBODYNE

The AWC Silencers Thor Turbodyne is compact and effective. It is nearly half the weight as our renowned Turbodyne but with the same suppression. The Thor Turbodyne is the quietest .50 caliber suppressor available on the market. The Thor Turbodyne can be fitted to most semi-auto and bolt-action .50 BMG rifles, mounting directly to the current muzzle break threads without modification to the gun.

• Caliber .50
• Length 15.7in
• Diameter 1.985in
• Weight 3 lbs, 3oz
• Factory-Tested Sound Reduction 28
• Materials TITANIUM
• Finish BLACK, OLIVE DRAB, FDE
• MSRP (USD) $ 1,785
• awcsilencers.com

BARRETT

AML 338

Made of a lightweight, high strength Titanium alloy, which is 100% CNC machined and orbital welded to minimize weight without sacrificing durability. The AM suppressors are designed to quickly attach to a recoil-reducing Barrett muzzle brake, which offers high decibel reduction and other key factors such as accuracy, repeatable point of impact shift, and flash reduction—even in low light environments.

• Caliber: 338 and less
• Length: 10.3in (262 mm)
• Diameter: 1.9in (48 mm)
• Weight: 1.6 lbs (0.7 kg)
• Factory-Tested Sound Reduction: -23-28 dB
• Materials: Titanium Alloy w/ 4140 Lock Ring
• Finish: Coyote
• MSRP (USD): $1,775
• barrett.net

BARRETT

QDL

Specifically engineered for the M107A1, Model 99, and Model 95, the QDL suppressor attaches to the rifle via proprietary recoil reducing muzzle brake while maintaining 100% function and reliability. The baffle stack features redundant 360 degree CNC welds to contain the extreme pressures, while the suppressor’s dual-layered tube is constructed of high strength alloys to ensure both durability and safety in any condition.

• Caliber: 50 BMG
• Length: 14.8in (376 mm)
• Diameter: 2.5in (64 mm)
• Weight: 4.9 lbs (2.2 kg)
• Factory-Tested Sound Reduction: 23 dB
• Materials: 4130 Steel
• Finish: Black and Flat Dark Earth
• MSRP (USD): $2,978
• barrett.net

B&T AG – SWITZERLAND

Reduced Backpressure Suppressor

The Reduced BackpressureSuppressor (RBS) is specifically designed to meet the request of several NATO armies. The request was to develop a suppressor that will reduce the muzzle flash, sound impulse and most importantly reduce the amount of backpressure that is released into the operator’s face. The suppressor comes in both 5.56mm and 7.62mm calibers for all assault rifles and machine guns using any flash hider or mounted directly on the barrel thread.

• Caliber 5.56mm / 7.62mm
• Length 169mm / 202mm
• Diameter 49mm / 54mm
• Weight 650g / 850g
• Factory-Tested Sound Reduction 22dB / 23dB
• Materials Inconel
• Finish Grey and Black
• MSRP (USD) $1,145
• bt-arms.com / bt-ag.ch

B&T AG – SWITZERLAND

ROTEX-X

The ROTEX-X suppressor is an evolution of the ROTEX-V. The ROTEX family of suppressors has become the suppressor of choice for many European small arms OEMs and NATO Special Forces, Police Intervention and SEK Teams. It is available in 5.56mm and 7.62mm calibers in both standard and compact sizes. It will fit on any NATO “birdcage” flash hider. The mounting system is rock solid and easy to remove.

• Caliber 5.56mm / 7.62mm
• Length 169mm / 198mm
• Diameter 39mm / 39mm
• Weight 500g / 590g
• Factory-Tested Sound Reduction 28dB / 25dB
• Materials Inconel
• Finish Grey and Black
• MSRP (USD) $1,145
• bt-arms.com / bt-ag.ch

TACTICAL SOLUTIONS

PAC-LITE IV TSS

Tactical Solutions’ PAC-LITE IV TSS™ is the only integrally suppressed upper available for the Ruger Mark IV™ and Mark IV 22/45™ and includes a patent pending, muzzle-end front sight system. At only 12 ounces, this lightweight, accurate, integrally suppressed .22 LR pistol barrel features titanium interlocking baffles and a patented, stainless steel split tube for easy service and cleaning.

• Caliber .22 LR
• Length 12.75in
• Diameter 1.0in
• Weight 12oz
• Factory-Tested Sound Reduction 38dB
• Materials Aluminum, Titanium, Stainless Steel
• Finish Anodize
• MSRP (USD) $635
• tacticalsol.com

TACTICAL SOLUTIONS

AERIS

At a mere 3 ounces and 3 inches in length, Tactical Solutions’ AERIS is an economical, multi-caliber, lightweight, user-serviceable and compact suppressor. It is constructed with durable titanium baffles, and its patented split-tube design makes for easy removal of the baffle stack for easy cleaning and maintenance.

• Caliber .22LR / .17HM2 / .22WMR / .17HMR / .17WSM
• Length 3.0in
• Diameter 1.0in
• Weight 3oz
• Factory-Tested Sound Reduction 21dB
• Materials Titanium, Stainless Steel
• Finish Matte Black Cerakote
• MSRP (USD) $297
• tacticalsol.com

TiON, Inc.

DRAGOON 450 Bushmaster

The Dragoon 450 Bushmaster is rated for .450B and .458 SOCOM semi-auto and all Bolt/ Lever Action calibers .22lr thru .450B.  Breakthrough dB reduction for .450B, .458 SOCOM and 9mm Luger.  All titanium and serviceable down to piece parts.  Patented Gas Indexing Technology (GIT) baffles are configurable by operator when used with pistol calibers.  Direct thread barrel mounts are changeable for varying platforms.

• Caliber: .450 Bushmaster
• Length: 10.375 Inch
• Diameter: 1.375 Inch
• Weight: 11.8-12 Oz (Mount Dependent)
• Factory-Tested Sound Reduction: 133 dB at Ear (Bolt Gun)
• 138 dB at Muzzle
• Materials: Titanium
• Finish: Cerakote
• MSRP (USD): $ 1150.00 (includes 1 mount)
• tioninc.com

TiON, Inc.

DRAGOON QD 350

The Dragoon QD 350 rifle suppressor, machined from solid titanium bar stock, creates an extremely durable, lightweight suppressor without welds or failure points. Serviceable down to the piece parts and provides top-rated sound reduction across the entire caliber range. Optimized for rifles & pistols w/ braces chambered in 9mm and .350 Legend, but very good performance with .22lr and .300 Blackout.  Additional mounts available. SEE THE DRAGOON’S PROPRIETARY 2 SECOND TITANIUM QUICK DETACH MOUNT!

• Caliber: .350 LEGEND
• Length: 8.0 Inch
• Diameter: 1.375 Inch
• Weight: 12.2 oz
• Factory-Tested Sound Reduction: 131 dB at Ear
• 133 dB at Muzzle
• Materials: Titanium
• Finish: Cerakote
• MSRP (USD): $ 1285.00 (includes 1 mount)
• tioninc.com

YANKEE HILL MACHINE

NITRO N20

In creating its next modular suppressor, Yankee Hill Machine (YHM) determined the material of choice must be titanium for its extreme lightweight and durable properties. Enter the NITRO N20, YHM’s newest iteration of its modular suppressor range designed around the tactical shooter. The NITRO N20 achieves mission-specific modularity by providing a plethora of mounting options and a choice between short and long configurations. The NITRO N20 is full-auto rated with subsonic ammunition and will accommodate .17HMR to 9mm and .308Win.

• Caliber .17HMR-9mm /.308Win
• Length 5.4in (short configuration) / 7.5in (long configuration)
• Diameter 1.562in
• Weight 6.5oz (short) / 10oz (long)
• Factory-Tested Sound Reduction 126dB (9mm long configuration)
• Materials Titanium
• Finish Matte Black Cerakote
• MSRP (USD) $1,249
• YHM.net

Yankee Hill Machine

R9 9mm

When Yankee Hill Machine (YHM) set out to make the R9, the goal was a 9mm suppressor capable of handling high volumes of fire and able to run other calibers such as .300 BLK and .308 Win. Primarily focused on suppressing 9mm (specifically submachine guns and SBRs), it was made at a budget-friendly price while maintaining the durability one expects from YHM. The R9 is capable of being used on a handgun in conjunction with our Nielsen Booster Assembly.

• Caliber 17HMR-9mm /.308Win
• Length 5.2in
• Diameter 1.562in
• Weight 10.7oz
• Factory-Tested Sound Reduction 123dB (9mm 4.25in barrel)
• Materials 17-4 PH Stainless Steel
• Finish Matte Black Cerakote
• MSRP (USD) $449
• YHM.net

In the few years of its existence, Qual-A-Tec developed a reputation as one of the most innovative developers of suppressors. Very little was written about their products since they were almost exclusively sold to the U.S. Military and the majority of those went to the Navy. The shield of secrecy was tightly held between the media and the user. I will not violate that shield and will instead try to describe the technologies that were developed.

Let me digress for a few moments to relate how I became involved in the Qual-A-Tec saga. Unlike many silencer designers, my involvement in suppressors came as a result of my job and not from some personal desire to build suppressors for myself. As a mechanical engineer working for the Naval Weapons Support Center, Crane, Indiana, I was assigned to work with the Joint Service Small Arms Program (JSSAP). Major David Baskett has to take the blame (or credit) for getting me involved in suppressors. He worked for JSSAP at Picatinny Arsenal and had become involved with trying to support the Special Operations Forces with special small arms developments. We worked together to establish a group within JSSAP whose job it would be to perform special developments for low demand weapon systems (including, of course, suppressors). We traveled the country searching out suppressors that could be useful for these special military operators. This effort started in the late 1970’s and to those who remember, there was not a lot of suppressor development going on in this country at that time. I recall that the 22 caliber Suppressors that we looked at were all 1.38 to 1.75 inch diameter cans with flat washer baffles. While they were relatively quiet, they were large, heavy and bulky. Looking back, there has been a tremendous amount of improvement made in suppressor technology in the last 20 years. I will try to relate my experiences throughout this “golden age” of suppressor development. I am not a historian, and did not do a good job of documenting the suppressors I evaluated so my look at this history is from the technological developments.

The suppressors of the 1970’s were primarily of two styles. The Navy was using the S&W pistols with the “Hush Puppy” wipe style of suppressors. This System had been developed by the Navy at White Oak and had inserts made with polyurethane wipes and special subsonic ammunition. The problem with the system was that the chamber pressure of the cartridges was quite high (loaded by Super-El) and that led to problems with ejecting the round after unlocking the slide. The other problem was that the terminal effects were poor. I recall a report from a SEAL who had the task to take out the “guard goose” at a Village in Vietnam. He shot the goose twice with the Hush Puppy and only succeeded in making the goose mad and very noisy. Obviously, this lack of lethality led to the guns being left behind during “real” missions. The other suppressors were a mixture of rather simplistic flat washer type baffles in rather large diameter tubes. Many were made from aluminum to keep the weight down and almost universally were not well suited to the real life missions of the military user. What was clearly needed was a real system. Unfortunately that approach was not to become a reality for quite a few years.

The advent of limited partnerships and capital write-offs for R&D expenses lead to some creative funding for a serious development of suppressors. Charles A. (Mickey) Finn met tax attorney Frederick R. Schumacher who set up these limited partnerships to fund development of suppressors specifically for military customers. Qual-A-Tec was the corporation formed to perform this effort. As one of the military customers, Crane took advantage of the offers from Mickey Finn to try and develop new technologies. This happened simultaneously with Richard Marcinko forming up his “Mob Six.” So here was a user in need of new good hardware and a developer in need of a project. Each needed and used the other. This was far from a marriage. It was more a case of consensual intercourse. When Maj. Baskett and I first tested Mickey Finn’s suppressors they were quieter than anything else we had found. At that time he was using simple flat washer baffles spaced at approximately .25 inches. The rear baffles usually had four holes near the outer edge that helped keep the decibel reading lower, but the real key to the suppressor’s performance was keeping the bore though the suppressor to an absolute minimum in relation to the projectile diameter. The 20 or more baffles of course added a lot of weight to the system. While I was still at Crane, Maj. Baskett arranged for me to take one of these to Washington for a demonstration to some clandestine operators. Being young and naive I put through the travel orders and carried the suppressed .22 Ruger pistol to Washington National. I met Dave at the entrance to the Pentagon and we proceeded to go inside to conduct a demo in one of the vaulted rooms. Phone books were gathered and used as the target. I remember everyone present was duly impressed. After the test I packed the gun and ammo into a tote bag and out the door we went. Dave and I repeated the tests later that night at the hotel room and the next day I was back in Indiana. Looking back, I see how utterly stupid one young engineer can be. I guess that by that time I was hooked. Not so much on the desire to develop suppressors but to try and help the Special Operations users. There was so much clandestine paranoia that the user simply would not go out and find the best suppressors available. That has changed a lot in the last 15 years due to the formation of USSOCOM. Back in the 70’s and early 80’s each Special Operations Group choose its own sources for specialized hardware and these sources were closely guarded secrets. Each group wanted the ability to claim that they were better equipped to handle a specific task than another group. This rivalry really held the total development process back. Things have greatly improved. Today there is open competition and users writing well thought out requirement documents. Today’s Special Forces operators are getting much better equipment than those in years past and more will come home from their missions because of it.

Mickey was able to get a few small contracts with Crane. One of the first involved was a .50 caliber Suppressor for a SS41 German rifle that came from the Aberdeen Museum. Crane took an accuracy barrel and sent it to Mickey along with a drawing. Mickey had located a lathe that could form the dual start course pitched metric thread. This weapon was used to establish the base line characteristics for a .50 cal. sniper rifle. Mickey built a suppressor that was used for the proof of concept. This suppressor was a large aluminum affair with titanium flat washer baffles. The first time we tried to mount this suppressor to the rifle happened at the SEAL’S Desert facility. The threads for the suppressor had not been machined properly, but because it was hard to tell whether it was fully seated on the weapon or not we decided to test it. The first shot was fired by myself and it launched the suppressor 20 to 30 feet down range. Needless to say the recoil was quite severe. The suppressor was only a little worse for the error and by the next day was properly mounted and successfully tested. This was probably the first successful .50 cal suppressor ever built.

Mickey also got another contract to improve suppressors for Ingram MAC 10s and the Hush Puppy’s that Mob Six needed. The Ingram suppressors were taken apart and the aluminum spiral cut baffles were replaced with flat washers and spacers. Testing showed that the sound pressure level reduction was improved by six to eight decibels. For the Hush Puppies a baffle was added behind the wipe unit and that improved its reduction by three decibels. The problems happened when the users started using the guns hard and didn’t keep the suppressors locked on the guns tight enough. To anyone who has handled an Ingram much it is easily seen that the alignment goes to heck very rapidly when the suppressor gets loose. The original spiral baffles had a tubular bore from one end of the suppressor to the other. This guided the bullet out of the suppressor whether the suppressor was tight to the weapon or not. The washer type baffles did not do this and eventually a round exited the side of one of the cans. The first of many lessons I learned about the SEALS is that they do not take particularly good care of their weapons. To many who look at their machine guns as investments or objects to study, realizing that the SEALS look at them as disposable tools, made to be used and abused as necessary is a revelation. To SEALS, there are two types of tools, shit and good shit. Shit tools have to be carried, cleaned, maintained and still don’t work right. Good shit needs minimal cleaning and maintenance and does its job, as advertised, every time. Good shit doesn’t get in the way of “Miller Time”. Once this got properly engraved into my mind I started looking at suppressors (and other weapons) from a different light. What must this tool become to be truly useful to these users? That became the driving force behind all of my future suppressor designs.

I had my mid-life crisis, resigned from Crane and went to work for Mickey Finn at Qual-A-Tec. This was not a financially advantageous move on my part and I owe a lot to my family for supporting this choice. I have to look at this as another educational experience on my part. Because Qual-A-Tec didn’t have to show a profit, we were able to devote a lot of time and money to improving suppressor design. Mickey is a very talented man and had a good analytical mind that understood the goals of improving the workings of suppressors. We were able to build and test two or three different designs a day for a couple of years. All of this resulted in a very good suppressor education for me. I mostly documented what was accomplished and had input into the development experiments. I also helped prepare and proofread all of the patent applications. Bob McDonald came to the company a little earlier than I did. Bob ran the shop and built most of the experimental hardware. He also provided input into the design but primarily brought forth new manufacturing techniques. Other people were involved but this was the core of the design effort. The first big breakthrough was the thicker flat baffle with the angled hole through the center. This baffle proved so effective that the diameter of the suppressor tubes were able to be dramatically reduced. I think that each baffle design has an optimum diameter associated with it for each caliber. It became apparent to us that this new baffle had to have higher gas pressure behind it to optimize its performance.

Let me digress a bit here to discuss some of the physics that makes a suppressor work. The measure of the sound from a suppressor is a measure of peak pressure at the muzzle exit caused by the escaping gas and projectile. A suppressor’s job, then, is to keep the pressure at the muzzle at a minimum. The first applicable physics equation is: pv=RT ; also known as the ideal gas law. In that equation p is pressure, v is volume per unit weight of the gas, R is a gas constant, and T is temperature in Degrees Rankin (degrees Fahrenheit plus 459.69). We are obviously not dealing with an ideal gas but some generalities can be made from this equation. First is that if you lower the temperature of the gas you lower the pressure. Likewise if you increase the volume in which the gas resides you also lower the pressure. The next thing that physics will show you is that turbulence causes flow to be reduced. Thus two things that a suppressor must do well are to take the temperature out of the gas and to restrict gas flow by causing turbulence. More efficient suppressors (in terms of decibel reduction) will get hotter in fewer shots than inefficient suppressors. This of course can lead to problems in suppressors for full automatic firearms. That is why material choices for suppressors are so important. They must absorb the heat from intimate contact with the gas as it travels through the suppressor yet conduct that heat rapidly to the outside of the suppressor. There are a few suppressor designers who think and even have patented suppressors based upon other concepts such as noise cancellation. I believe that the performance of their suppressors can be better explained with the physics of temperature reduction and turbulence creation. By the way, this education took several years to sink into this thick skull of mine. Of course knowing this will not make you a good suppressor designer. Applying these physical principals to hardware is still difficult. Looking at suppressors from this aspect will, however, lead the designer to better suppression concepts.

The suppressors which were developed at Qual-A-Tec began to shrink in total volume as the slant face baffles were improved. The spacers between the baffles also have a direct bearing on the efficiency of the suppressor. Like everyone else we started with simple tubular spacers of various lengths. The next generation we fondly called the “crank shaft” because the spacers were welded to the baffles and were undersize tubes with a single port that aligned with the output flow from the slanted baffle. The baffles were sometimes rotated 90 degrees at each baffle thus the crank shaft shape. These suppressors worked well in rifle calibers and some were built in 9mm as well. The next big step forward was the addition of a deep cut into the thickness of the baffle. This cut was joined with cuts from the back along the sides of the angled central bore. Three holes were then drilled to allow the gas which got compressed into this chamber to flow downward along the angled central bore. These baffles had some structural problems, which were eventually cured by adding strips of tubing between the two walls. We again went to the spacer design to gain some more sound pressure reduction. The final choice was a cone that was machined directly on the end of the baffle. This proved to be very quiet but lacked the structural strength to prevent the baffle from collapsing on itself when the pressures or temperatures of the suppressor got too high. This baffle was licensed to H&K and people familiar with their products from the mid to late 1980’s will recognize this baffle.

Qual-A-Tec made some significant advances in the state of the art of suppressors in the few years it was in existence. It probably built less than 500 suppressors and most of those went to military customers. Very few of these suppressors ever made it into private hands except as products built under license by H&K and AWC Systems Technology. It obviously takes a lot of business savvy to make a profit in the suppressor market and unfortunately that was not present in the Qual-A-Tec organization. It was an interesting period of time and I learned a lot from my involvement. Hopefully the military users of the suppressors that have their lineage through the Qual-A-Tec years have gotten superior hardware as a result of this company’s existence.

LIBERTY SUPPRESSORS

Whitetail Integral Bolt Rifle

We developed the Whitetail for the hunter in mind specifically. Most silencer designs either are centered on the casual shooter or the tactical community, but none really addresses the needs of the American hunter directly. Liberty Suppressors’ silencer is built with a grade 9 Titanium tube and an aircraft aluminum rear support to reduce weight of the assembly. The blast diffuser and the core are both made from stainless steel for durability due to the blast energy impingement that they are subjected to during use. The core is retained by means of a standard “off the shelf” 3/8-inch drive ratchet with a special profile milled in the front of the core, preventing the need for special tools for disassembly during routine maintenance. The overall length of the package is designed to mimic an unsuppressed hunting rifle as closely as possible. We also virtually matched the weight of the original unsuppressed rifle, by keeping the weight down in the suppressor module. This creates a package that is light, quiet and durable for the hunter in the field.

• MODEL : Whitetail 
• CALIBER: 6.5mm (6.5 Creedmoor) 
• LENGTH :13.5in 
• DIAMETER: 1.375in 
• WEIGHT: 6.5lbs 
• FACTORY TESTED SOUND REDUCTION: N/A 
• MATERIALS: Titanium/Aluminum/Stainless steel 
• FINISH: Graphite Black Cerakote 
• MSRP(USD): $999
• libertycans.net

LIBERTY SUPPRESSORS

Zulu Integral AR-15 Upper

The Zulu is a balance between suppression, accuracy, backpressure and balance. This integral is designed to mitigate the excessive back pressures generated by the typical AR-15 platform, and the suppressor’s flow-for-ward design gets the gas away from the shooter better than many other 556 suppressors on the market.

• MODEL: Zulu 
• CALIBER: .223 Wylde 
• LENGTH: 16.6in 
• DIAMETER: 1.625in 
• WEIGHT: Stripped upper–3.7lbs 
• FACTORY TESTED SOUND REDUCTION: N/A 
• MATERIALS: Titanium/ Inconel / Stainless steel 
• FINISH: Graphite Black Cerakote 
• MSRP(USD): $1550
• libertycans.net

B&T

Mounted Machine Gun Suppressor

The B&T Mounted Machine Gun Suppressor offers various advantages to the user. Besides the obvious purpose of reducing the sound of the gun more than 14dB, which makes command and communication easier, reduction of the muzzle flash is of paramount importance. As the muzzle flash gives away the position of the gun immediately, its reduction greatly adds to the safety of the shooter as its position is less visible, especially in the hours of twilight or darkness.
As opposed to other designs made by B&T, this suppressor is designed for use with mounted weapons; the weight of the suppressor, therefore, was not of a primary importance. B&T produces other suppressors which are lighter and better suited for dismounted use.

• MODEL: Mounted Machine Gun Suppressor 
• CALIBER: 5.56mm (.223) / 7.62mm (.308) 
• LENGTH:190mm (155mm extending gun) 
• DIAMETER: 48mm 
• WEIGHT: 1.0kg 
• FACTORY-TESTED SOUND REDUCTION: ca. 14dB 
• MATERIALS: Inconel / Thermax 
• FINISH: Sandblasted / Grey 
• MSRP (USD): $ TBA 
• bt-ag.ch

GEMTECH

Lunar 45

The GEMTECH Lunar 45 is the solution for shooters suppressing a variety of platforms and pistol calibers. Constructed from military grade aluminum and titanium, the Lunar 45 offers durability and strength without excess weight. This modular design is hearing safe in both configurations, and supported by a wide range of mounting accessories.

• MODEL: Lunar 45 
• CALIBER: 45 Auto 
• LENGTH: 8in Long, 6.9in Short 
• DIAMETER: 1.375in 
• WEIGHT:12.3oz Long, 10.9oz Short 
• FACTORY-TESTED SOUND REDUCTION: N/A 
• MATERIALS: 6AL4V Titanium, 7075 Aluminum 
• FINISH: Matte Black Type III Hard Coat Anodize 
• MSRP (USD): $799 
• gemtech.com

GEMTECH

ONE

The GEMTECH ONE is the solution for shooters seeking maximum versatility and durability. Constructed from Inconel and titanium, the ONE offers unwavering performance on short-bar-reled 5.56 through 300WM rifles. Featuring an interchangeable thread mount/ Quickmount™ system the ONE can be mounted to a vast range of rifle platforms and calibers.

• MODEL: ONE
• CALIBER: 300 WIN MAG 
• LENGTH: 7.8in 
• DIAMETER: 1.625in 
• WEIGHT: 17.4oz 
• FACTORY-TESTED SOUND REDUCTION: N/A 
• MATERIALS: Inconel 718, 6AL4V Titanium 
• FINISH: Matte Black High-Temp Cerakote® 
• MSRP (USD): $1,099
• gemtech.com

DANIEL DEFENSE

DD WAVE

The DD WAVE sound suppressor’s cascading baffle geometry more effectively attenuates sound than simpler baffle styles. A unique one-piece, 3D-printed baffle and tube eliminate the need for welds—typically the weakest points of a traditional suppressor. Constructed of nickel-based superalloy, stainless steel and Titanium—and then Cera-kote-coated—the DD WAVE is fiercely strong yet lightweight, making it durable and reliable for full-auto use. danieldefense.com

• MODEL: DD WAVE 
• CALIBER(S): .17 HMR to .300 Win Mag 
• LENGTH: 7.6in 
• DIAMETER: 1.5in 
• WEIGHT: 17.2oz 
• FACTORY-TESTED SOUND REDUCTION: N/A 
• MATERIALS: Nickel-based superalloy, stainless steel and Titanium construction for durability 
• FINISH: Cerakote 
• MSRP (USD): $850 for the QD/$799 for DT 
• danieldefense.com

SILENT LEGION SUPPRESSORS

7.62×39 Quick Detach SL-AK

The Silent Legion SL-AK is your answer for a high-performance suppression system for 7.62x39mm platforms such as the AK-47. It comes standard with the Bi-Lock Quick Detach mounting system, as well as the two Bi-Lock QD flash hiders that cover the most common thread pitches on AK firearms.

• MODEL: SL-AK 
• CALIBER: 7.62mm
• LENGTH: 7.75in
• DIAMETER: 1.50in
• WEIGHT: 17oz
• FACTORY-TESTED SOUND REDUCTION: 32dB
• MATERIALS: Titanium
• FINISH: High Temperature Cerakote
• MSRP (USD): $989
• silentlegion.com

SILENT LEGION SUPPRESSORS

.450 Bushmaster .458 SOCOM

Designed with the straight-wall cartridge hunter in mind, the durable .450 Bushmaster.458 SOCOM suppressor is the perfect thing to harness the energy of this heavy hitting round and tame the noise as well as the recoil. Direct Thread comes with Suppressor Retention System.

• MODEL: SL-BM 
• CALIBER: .450 Bushmaster/.458 SOCOM 
• LENGTH: 8.75in 
• DIAMETER: 1.50in 
• WEIGHT: 18oz 
• FACTORY-TESTED SOUND REDUCTION: 30dB 
• MATERIALS: Titanium 
• FINISH: Cerakote 
• MSRP (USD): $1,048 
• silentlegion.com

FREEDOM ARMORY

Dragoon 7.62 CQB

The Dragoon 7.62 CQB suppressor is machined from solid Titanium bar stock creating an extremely durable, lightweight suppressor without welds or failure points. It’s serviceable down to the piece parts and provides top-rated sound reduction across the entire caliber range. See the Dragoon’s proprietary 2-second Titanium quick-detach mount!

• MODEL: DRAGOON CQB 
• CALIBER: 7.62 
• LENGTH: 7.5in 
• DIAMETER: 1.375in 
• WEIGHT: 11oz 
• FACTORY-TESTED SOUND REDUCTION: 138dB at muzzle | 132dB at ear 
• MATERIALS: Titanium 
• FINISH: Cerakote 
• MSRP (USD): $1095 
• tioninc.com

ELITE IRON

STFU LITE

The STFU LITE was designed for hunting and light-use applications. The Titanium construction makes this suppressor light and easy to shoot out in the field. Designed to be used on .30 / 06 or smaller cartridges.

• MODEL: STFU LITE 
• CALIBER: .308, .30/06 
• LENGTH: 7.875in 
• DIAMETER: 1.625in 
• WEIGHT: 15oz 
• FACTORY-TESTED SOUND REDUCTION: 27.5dB 
• MATERIALS: Tube: Grade 9 Titanium Internals: Grade 5 Titanium 
• FINISH: Black Cerakote 
• MSRP (USD): $1095
• EliteIron.com

ELITE IRON

DELTA LITE 

he DELTA has been very popular. In response to this, we have created the DELTA LITE similar performance in a lighter package. The DELTA LITE suppressor is available in a variety of different popular calibers; it is a favorite among varmint hunters. This suppressor is suitable for both bolt-action and semiauto rifles.

• MODEL: DELTA LITE 
• CALIBER: .223, 22-250, .243 or 6.5 
• LENGTH: 7.5in 
• DIAMETER: 1.5in 
• WEIGHT: 12oz 
• FACTORY-TESTED SOUND REDUCTION: 34dB 
• MATERIALS: Tube: Grade 9 Titanium Internals: Grade 5 Titanium 
• FINISH: Black Cerakote 
• MSRP (USD): $950 
• EliteIron.com

By Paul Evancoe

Hollywood movies depict sound suppressors as “silencing” the report of a handgun or rifle to an almost inaudible “puff – puff’” sound. Most have no idea why or how suppressors work, why some designs work better than others, what role the choice of ammunition plays, or other critical operating dynamics that involve gun design and the unavoidable laws of physics.

Quite simply, a sound suppressor works by slowing the sonic (traveling above the speed of sound) swirling high velocity gases generated by the propellant’s burn to sub-sonic speeds as those gases leave the suppressor’s muzzle end. It took a modern scientific understanding of hydrodynamics to recognize that sound suppression pivoted upon two variables – reducing bullet velocity to less than the speed of sound (1,126 feet per second at sea level) and slowing the sonic high velocity gases generated by propellant combustion to sub-sonic velocity. This slowing of the swirling sonic velocity gases is scientifically described as disrupting the hydrodynamic axially rotating pipe flow – well; now you know.

The first condition for suppressing the firing sound (report) made by any firearm is to use sub-sonic ammunition (or porting the barrel itself to reduce the speed by reducing volume of propellant gases). Sub-sonic ammo leaves the muzzle below the speed of sound, with a velocity less than 1,126 feet per second. This is most often accomplished by “down-loading” the ammunition by either loading it with a slow burning sub-sonic propellant (smokeless powder), or using fast burning propellant ammunition in conjunction with a short-barreled gun thereby reducing propellant burn time which subsequently reduces bullet velocity.

The use of sonic rounds, especially in long guns like sniper rifles, that snap, crack and pop as they break the sound barrier in flight downrange is commonplace. The advantage of using a suppressor in conjunction with high velocity ammunition is that locating the shooter’s exact firing position is made difficult and it further reduces the requirement for ear protection by the shooter, allowing better situational awareness. Secondly, there is little loss of muzzle velocity or impact energy beyond that which would be experienced without the suppressor. Unless the gun has a floating barrel, accuracy usually isn’t affected excepting predicable shifts in group point of impact.

Using a suppressor on a floating barrel involves several factors that are many times not considered. A floating barrel improves a long gun’s accuracy. Suppressors add weight to the barrel’s muzzle-end. Adding weight to the muzzle-end of a floating barrel will change barrel harmonics thereby reducing accuracy. This can somewhat be overcome with a heavy target (“bull”) barrel that is structurally robust and not as susceptible to harmonic effects. However, the added weight of a target barrel and a sound suppressor isn’t always desirable in a tactical environment where mobility and man-carried portability is a necessity.

Even with a suppressor and sub-sonic ammunition, there are several steps that can be taken to further reduce the firing signature. The first is simple. For maximum suppressor efficiency, the gun needs to be “locked up.” This means a manually operated bolt gun with a suppressor offers less of a sound signature than a semi-automatic gun of identical barrel length with the same suppressor shooting the same ammunition. Here’s why. Upon discharge, a semi-automatic bolt strokes rearward to eject the spent brass. The bolt’s backstroke allows some of the high velocity propellant gases generated upon firing to escape the breech and that makes sound. Additionally, the mechanical operation of the retracting and advancing bolt makes a mechanical sound that, in most firearms, both rifle and pistol, approximates the same noise made when manually jacking the bolt/slide back and forth when chambering or unloading the gun. It’s noisy and can be heard.

The mechanical operation (and associated mechanical noise) of a semi-automatic (or automatic) rifle or pistol can be eliminated by the installation of a lock-up lever that prevents the bolt or slide from cycling when the gun is fired. This forces all the gases of combustion to exit from the muzzle end of the gun through the sound suppressor. The down side of this is that it relegates the firearm to single fire requiring the shooter to unlock the slide/bolt, and manually eject the spent brass and reload (manually cycle) the gun. Clearly, where optimal sound suppression is necessary and only one shot is required to get the job done, this option is desirable. Where multiple shots may be necessary, the use of a slide/bolt lock is suicidal.

Incidentally, using a suppressor with a revolver is only done in Hollywood. If you’ve ever seen a revolver fired at night you will have observed the flames emitted between the cylinder and the barrel. No matter how well it’s fitted, the gap between the cylinder and the barrel always allows gas to escape and that means it “bleeds” noise. Don’t waste money putting a suppressor on a revolver.

As mentioned previously, along with other factors, the selection of ammunition is important. The propellant’s burn velocity, amount of propellant, bullet weight and barrel length (providing enough length for a full propellant burn), are directly proportional to bullet (projectile) muzzle velocity and effectiveness on target impact. When using a suppressor, the choice of ammunition must be carefully considered. Obviously, ammunition that offers the highest energy on target impact with the lowest sound signature is most desirable. Sub-sonic ammunition is commercially available for many of the more commonly used calibers. In fact, most pistol ammunition is already sub-sonic, or very close. A bullet velocity of less than 1,200 FPS, even though it is not advertised as sub-sonic, will work just fine in conjunction with most short barrel pistols and sub-guns equipped with suppressors.

One of the most common problems encountered when using downloaded sub-sonic ammunition is that a self-loading (semi-automatic or automatic) firearm will many times not function reliably. This most often results from the bolt/slide not retracting backward with enough force to reliably eject the spent brass, or not stroking rearward far enough to pick up the next round from the magazine, chamber it and return to battery. Feed malfunctions and jams are commonplace unless the recoil spring/buffer mechanism is modified and tuned to properly operate the bolt/slide under reduced recoil (lower ammunition operating pressure). In most cases, this means that a gun modified to function with sub-sonic ammunition can then no longer safely shoot standard high velocity ammunition without damage to its operating system or the shooter. That’s the reason most guns that are modified to shoot sub-sonic ammunition are dedicated for that specific purpose.

The exception to this rule was perfected in the 1970s with the advent of the Electrical Discharge Machining (EDM) process. Using an EDM, a small gas-venting channel (groove) is cut inside the gun’s bore from a point behind the bullet of a chambered round to a measured point in front of it. When the gun is fired this channel vents high-pressure gas around the bullet slowing its travel down the bore to sub-sonic velocity. This permanent gun barrel adaptation permits the use of regular high velocity ammunition in sub-sonic suppressed applications.

So where did it all start? The evolution of sound suppressors began around the time smokeless propellant became the mainstay early in the 20th century. Wrapping a pistol in a towel or blanket reduced its sound signature. That worked fine for targets at arm’s length but not for distance. Around 1902, American inventor Hiram Percy Maxim, developed, patented and sold the first commercially available suppressors under the trademark, “Maxim Silencer.” Today there are 3 basic suppressor designs with internals that employ either screens, wipes or baffles (there are also some very clever hybrids) that are inserted inside a can-like outer housing of sorts and the can is attached to the muzzle end of the firearm. Let’s walk through these designs as they chronologically evolved and better understand them.

Screen-type Design. A prime example of a screen-type suppressor was used on WW-II vintage M3A1 .45ACP sub-machine guns (grease guns) carried by paratroopers. Some of these guns were specially fitted with screen-type sound suppressors. They worked by passing the high velocity gases escaping through a specially perforated barrel through dozens of screens inside the suppressor’s can (body). This slowed the gasses, all but stopped the Coriolis (natural tendency for gases to spin around an axis) and quietly vented the overpressure to
atmospheric pressure.

A screen-type suppressor is perhaps one of the most elegant yet least sophisticated and cheapest designs to build and maintain. The suppressor body (“can”) is made from a piece of 2 1/2 inch diameter (approx.) seamless steel pipe about 12 inches long. It has a threaded removable faceplate end cap with a centered .45 inch bullet exit hole. The threads are precision optical-type 60 degree included threads. The faceplate’s outside edge has a straight knurl to improve the finger grip when tightening and untightening it to the can. The other end of the can has a permanently welded end cap that is threaded to mate with the shoulder threads on the gun barrel’s breech end. When it’s screwed onto the gun, the perforated gun barrel extends completely inside the can tightening flush with the gun’s breech.
 
The suppressor’s internals are made from common 80 to 120 mesh metal window screen punched out to fit the inside diameter of the 2 1/2 inch can. A hole is also punched exactly into the center of each piece large enough to slide over the perforated gun barrel. When enough of these screens are punched out (it literally takes dozens) to completely fill the inside of the can, layered one directly against the other, they are loaded into the can by first stacking them onto a center diameter wooden or metal dowel.  Then, using the dowel, they are inserted inside the can as a whole element. The can’s threaded end cap is secured finger tight and the can is screwed onto the gun’s muzzle. It’s now ready to shoot.
 
After hundreds of rounds fired the screens tend to clog up with carbon and unburned powder residue. To clean the suppressor, the can is removed from the gun. The threaded end cap is removed. The dowel is reinserted into the center hole of the screens. The suppressor is up ended and the screens are all removed at once on the dowel. The screens and dowel are submerged in gun cleaning solvent.  When the dirt is soft the screens are either individually brushed (field cleaning) or compressed air is used to blow out the dirt. The screens, using the dowel, are reinserted into the can, the end cap is replaced and the suppressor is ready for use again.

The advantage of this suppressor design is that it was cheap, low tech and it worked reliably. The downside was its weight from all the metal screens and robust steel housing. It also rusted if not maintained and some screen replacement was regularly necessary after sustained automatic fire because the heat of combustion and high velocity gases deteriorated the fragile screen material.
 
Wipe design. Of the 3 basic designs previously mentioned, the use of wipes followed the screen design. Wipes began appearing in suppressor design in the mid 1960s during the Vietnam War. A prime example of the operational use of a wipe suppressor was one used by U.S. Navy SEALs nicknamed the “Hush Puppy.” SEALs primarily operated at night. Sneaking into or around the small rice paddy villages and hamlets always meant risking compromise from barking dogs. The answer was a modified Smith and Wesson Model 39 with a Hush Puppy sound suppressor. A lot of dogs fell to this 9mm sub-sonic sound
suppressed pistol.

The wipe design is perhaps the quietest and smallest of all suppressor designs but it has the least lifespan and requires the most maintenance. It works by using a series of spaced rubber-like baffles called wipes, that the bullet passes through on its travel through the suppressor. In this design the bullet actually makes contact with the wipes that flex open and close as the bullet passes through them. This traps the propellant gasses inside the baffle chambers which results in a near complete sound suppression of the subsonic round to something equaling a pen tap on a desktop in a quiet room. Obviously the SEAL’s Model 39 was modified with a slide locking lever so it wouldn’t back stroke when fired. This dedicated single shot application proved wildly effective to quiet dogs as well as enemy combatants. Another example of the smallest wipe design used by the SEALs was a single fire suppressed gun used for assassination that was made to look like a ballpoint pen. The one shot gun fired a .22 cal. CB cap when the pen’s ballpoint extension button was pushed down. Its report was negligible and when fired at the base of the skull it was lethal.

In general, here’s how Hush Puppy wipe design works. The rubber wipes are punched out of 1/4 inch thick butyl rubber sheet material with an outside diameter that fits the inside diameter of the suppressor’s can. Each wipe has a small 1/8 inch hole in its center. Each rubber wipe is then carefully sliced into quarters (or sometimes sixths) that radiate from the center hole. The quartering cuts stop about ¼ inch from the wipe’s outer diameter so it remains intact looking much like a cut pizza with an uncut outer crust ring.

The rubber wipes are then inserted into the suppressor can with metal spacer rings separating each wipe. The spacer rings serve two purposes. They create small gas-catching chambers between each wipe and provide additional internal structural integrity that prevents the wipes from being torn away as the bullet passes through them. Because of the efficiency of the wipe design it can be made very small (scaled down to a particular application like the pen gun mentioned previously) and thus, very light. The down side of a wipe design is the fact that the bullet wears the wipes every time it passes through them. This translates to a suppressor that gets louder every time it’s fired. Most wipe designs only maintain their suppression integrity for about the first 10 shots. Then the wipes must be replaced with new wipes. Anything beyond 10 shots results in a sequential increase in the firing noise. At approximately 20 rounds there is essentially no longer any suppression left because the wipes have been worn away.

Baffle design. This design is most prevalent today with numerous types of exotic baffle shapes that range from cones to flat washer-like shapes along with the use of common to exotic metal to composite construction materials. In general terms, most all baffle designs work the same. They slow the sonic gases resulting from propellant combustion to sub-sonic speeds using baffled chambers and vent the gases harmlessly to the atmosphere. Baffle designs are also the most environmentally rugged, have the longest life expectancy and are the easiest to maintain. In short, they work and they last thousands of rounds.

Early baffle designs used little more than washer-like steel rings welded inside a pipe-like housing. Similar to the can used for screen-type and wipe designs, the baffled suppressor uses a can with a bottom end cap that mounts to the gun’s muzzle end and a front cap (usually threaded and removable for cleaning maintenance) on its bullet exit end. Beyond the visible can-like exterior, all comparison ends.

Around the early 1970s an out-of-the-box-thinking gun enthusiast and machinist by the name of Mickey Finn, began experimenting with the physics involved in suppressor technology. Finn was on a one man quest to increase the efficiency and shrink the size and weight of sound suppressors. Following in-depth trial and error experimentation, he recognized that the high velocity sonic gases resulting from propellant combustion could be radically slowed by creating baffles with angled machined cuts that created reverse flow venturi-like jets that redirected the high pressure gases in opposition to one another within each baffle chamber. He further realized that equal spacing of the baffle chambers was not optimum. Finn adjusted chamber spacing (and thus, volume) to account for the progressively slowing gasses thereby providing for optimal suppressor performance.

Finn began trial and error limited production of his uniquely designed suppressors and enjoyed radical success with the SEALs becoming his best customer. But the SEALs had a unique requirement that no one had previously met. After being submerged, the SEALs needed the capability to fire a flooded suppressor-equipped gun when taken directly out of the water without any drain time. Finn set to work on the suppressor technology while the Naval Surface Weapons Center’s China Lake and Crane Indiana laboratories modified the SEALs assault rifles and machineguns at critical points with drain holes and self-lubricious coatings.

The SEALs had previously tested Finn’s suppressors by firing them when only partially drained. They found, curiously, the suppressors were actually quieter when they contained some water, but why? A puff of steam-like vapor followed each shot until there was no water left inside the suppressor. Without the water the suppressor was a bit louder. After some hydrodynamic soul searching they arrived at an answer that forever changed the understanding of suppressor dynamics.

Finn’s opposing gas check baffle design efficiently reduced the size and weight of the suppressor. Adding additional gaseous particulate material (like water particles) to the mix slowed the sonic gases even more. The result was a hybrid suppressor that was called the “Greaser.” The Greaser while still using a reduced version of the ultra-sophisticated opposing gas check baffle design was altered to have its base end stuffed with several thumb loads of commonly available bearing grease (but any grease works) prior to mounting it on the gun. The result was additional sound suppression.

Here’s how it works. When the gun is fired the rapidly expanding high pressure sonic gases enter the bottom end of the suppressor where the grease is located. The gases instantly atomize some of the grease. The atomized grease thickens the suppressor’s internal atmosphere with a heavier (more viscous) medium that slows the gases more efficiently. This essentially allows a smaller suppressor to perform at about the same sound suppression level as a larger unit.

The down side of the Greaser is that it emits puffs of blue vapor/smoke until all the grease is expended. That notwithstanding, the greaser can be used like any other suppressor until the grease can be replaced. Regardless, the science behind this revolutionary concept in suppressor technology has been largely forgotten in today’s baffle designs. That said, many of today’s suppressor designs can accommodate the addition of grease or other more modern material, and operate quieter as a result. Most manufacturers either don’t know about this option, or won’t advertise it as an alternative because of potential maintenance/warranty issues.

A quick aside: How do you know when to clean a suppressor? The answer is simple. Follow the manufacturer’s suggested planned maintenance schedule. Or, as a field use rule of thumb, when a suppressor begins to get noticeably louder and louder – that’s an audible signal that the suppressor needs cleaning and/or maintenance.

Today’s baffle design offerings are numerous and their levels of design sophistication vary widely. Some work far better than others. Some look outwardly awesome but have inefficient internal designs. Some look unimpressive outwardly but work exceedingly well. A suppressor’s retail price doesn’t necessarily mean that you’re getting what you’re paying for either on the high or low end of the spectrum. After reading this article, you should now be better able to do some intelligent evaluation regarding suppressor design, maintainability and life expectancy. Choose wisely.

After participating for several decades in the silencer business, Gemtech is a very familiar name in the world of military weaponry. Their ability to continue manufacturing effective sound suppression systems to meet a constantly changing environment is a cornerstone they wear with pride. With a current industry desire for silencers to perform with shorter barrels combined with a heavier rate of fire, their answer is the new TREK and TREK-T.

The TREK series silencers not only meet the criteria for short barrel use with a fully automatic rating, but they do it in a very small and very light package without sacrificing sound reduction.

The TREK silencers are the shortest and quietest thread-mounted 5.56mm suppressors available in the Gemtech family. With an overall length of 5.7 inches and an outside diameter of 1.5 inches, the standard TREK is manufactured from Stainless Steel and Inconel and weighs 17.3 ounces. The TREK-T has the same measurements and is constructed of Inconel and Titanium. The weight of the TREK-T is an extremely light 10.3 ounces.

Live Fire Testing

It would be a disservice to our readers not to mention that we are very excited about the claims of durability with short barrels (>10.4 inches) and the ability to withstand fully automatic usage. When you combine the small size and effective sound reduction it makes it even more interesting. We are currently conducting long term testing on both the TREK and TREK-T silencers but we are so excited with the early findings we wanted to give you some initial impressions in the early stages of testing. Watch future issues of Small Arms Review for long term testing including precision accuracy, fully automatic usage and high round counts.

It is the unanimous opinion among all shooters participating in these tests that the TREK silencers are far quieter than what is expected. All ammo has been standard 55 grain and 62 grain FMJ from numerous manufacturers with similar performance in all areas. Both silencers are very comfortable with no hearing protection and fall far below the pain threshold for shooters and spectators. While some 5.56x45mm suppressors with supersonic ammo can still be slightly uncomfortable to shoot with no hearing protection over long periods, the Gemtech TREK does not fall into that category. We have not yet tested these with sound metering equipment thus far and are only going on practical sound reduction, but as several testers have noted, that is the best and most important test for those people who actually use them. A silencer that meters well but is still uncomfortable to shoot is far less desirable than one that is simply noticeably quiet to those behind and beside it. An interesting comment that keeps surfacing is that the TREK-T is even noticeably quieter than the standard TREK. The residual sound has a different “pitch” that is easier on the ears and has been the preferred of the two models.

During the accuracy phase of testing we have been pleased to find that the noticeable point of impact (POI) shift has been almost non-existent with each platform when the rifle is sighted in with a standard flash hider. At this phase in testing, all shooting has been with an EOTech Holographic Sight, off-hand at a range of 50 yards.

Conclusions

As mentioned earlier, we are only in the very early stages of some long term testing with the Gemtech TREK and TREK-T silencers. So far the results are very impressive and all test shooters have expressed in being involved through all phases of future testing. Our initial conclusions are the TREK family of silencers performs much better than we had anticipated and we are quite intrigued with the lightweight and quiet TREK-T. The performance is impressive when compared to other suppressors, much larger and heavier. And the lack of point of impact shift is also reason to be pleased.

Since our early impressions are based on what we consider the initial phases of a long term test, and it is important to understand that our “light usage” is usually equivalent to or surpasses many shooters regular to heavy use, we have little doubt that the TREK silencer family will fail to impress anyone who has the opportunity try one for themselves. The MSRP of the TREK is $525 and the TREK-T is $1,100.

Gemtech
P.O. Box 140618
Boise, ID 83714-0618
Ph: (208) 939-7222
Website: www.Gem-Tech.com

Affable, cheerful and humorous, the doctor appears to be a wonderful real-world example of Marcus Welby – except he carries a gun. His name is Dr. Phil Dater and it might have been his fascination with how things work that led the curious physician to first experiment with sound suppressors in the 1950s, and later in the basement workshop of a hospital where he worked. Given his interest in firearms and his understanding of the scientific method – form a hypothesis, test it through repeatable experimentation and modify accordingly – Dr. Dater naturally took to sound suppressors and has been involved in many of the seminal sound suppressor companies in the modern era. Of all the arcane areas of firearms, suppressors are the most firmly rooted in a “trial and error” design processes because no amount of computers can possibly calculate all the variables at work when a gunshot erupts.

Suppressors have intrigued me too, which is how I’ve come to be sitting in the front row of Dr. Dater’s two-day class on Suppressor History, Technology & Testing conducted at the GSA training contractor, Long Mountain Outfitters in Henderson, Nev. The class is open to anyone, although Dr. Dater insists his students be vetted to assure no one of dubious motivation sneaks in. His information is protected by ITAR regulations, so only DoS qualified foreign nationals can attend and Dr. Dater understandably prefers his competitors to not attend.

Our class consists of firearms engineers, enthusiasts who want to learn what they can, suppressor dealers who want to enhance their sales ability, and several U.S. government employees from various military branches. Unbeknownst to me at the time, a celebrity is sitting in the back of the room, Pulitzer Prize winning author Stephen Hunter.

Dr. Dater displays an assortment of suppressors – “cans” in the vernacular – and immediately makes full disclosure that he’s one of the principals of Gemtech, a suppressor manufacturer. He assures us that his class is non-brand-specific, but that he wants everyone to know he has an interest in Gemtech. “I’ll try not to flog our product as this is not a sales presentation,” he says amiably.

Suppressor Background

Suppressors date to the turn of the century when Hiram Percy Maxim, son of the legendary machine gun inventor of the same name, started the Maxim Silent Firearms Company. Our class later tests one of Hiram’s original cans and surprisingly performs right up with “modern” designs.

Dr. Dater mentions some other famous suppressor inventors such as Mitch Werbell, Mickey Finn, Reed Knight and Doug Olson, pointing out that all of their designs came from trial-and-error experimentation along with scientific and engineering principles. It’s clear he has respect and admiration for these pioneers of silence.

We then jump right into the subject. Dr. Dater explains the basic science of sound. Sound is a form of over-pressure which is measured with a ratio of pressures – reference pressure to measured pressure – expressed in a unit of measure named for another well-known experimenter of sound transmittal: Alexander Graham Bell. The unit is called a decibel.

A gunshot, Dr. Dater tells us, is the sudden release of hot, high pressure propellant gases exiting from the muzzle of a firearm. A second component of a gunshot, the sonic crack, is caused by the bullet travelling faster than the speed of sound, like the sonic boom of a high-speed jet.

Going back to high school physics, Dr. Dater asks the class how to decrease pressure. I brush back the fog of time and remember that pressure is equally affected by temperature and volume. “That’s right,” says Dr. Dater, “If you lower the temperature and increase the volume, pressure decreases. In its simplest form, that’s all a can does to reduce sound – decrease temperature, increase volume.”

Now comes the technical part. Sound is not only a factor of loudness – decibels – but also of duration. Think of tapping your car horn versus an ambulance blaring its siren. The duration of the siren is more damaging than the short toot of a horn, even if they’re the same number of decibels. This leads to a discussion of what constitutes “harmful” levels of sound, which in turn brings us to the U.S. military’s definition of sound measurement as defined in Mil-Std 147 4D.

We will hear a lot more about Mil-Std 147 4D before the class is over. It’s the gold standard of suppressors, the only acceptable measurement of performance. Because the scientific method of trial and error is so important to suppressor testing, having a defined standard like Mil-Std 147 4D is imperative.

Reasons For Suppressors

Thanks to Hollywood, suppressors are widely perceived as only being used by assassins. It may be true that some cans have been used to snipe an enemy (we dropped suppressed .45 ACP rifles to the Resistance during World War II) but in today’s tactical climate, the suppressor has far more benign uses.

With law enforcement switching to patrol rifles such as Colt Commandos, the number one reason for a suppressor is to protect the shooter’s hearing. Additionally, cans serve to enhance command-and-control, confuse or deceive the target, to shoot out street lights or guard dogs on drug raids, to conceal the origin of the shot, muzzle flash minimization and a host of other tactical reasons.

Suppressors are a restricted item in the U.S. because when the National Firearms Act was passed in 1934 in the middle of the Depression, where Fish & Game determined that suppressors were used by poachers trying to feed their families, as well as an unfounded Hollywood stigma that suppressors were for assassinations. The Judge Advocate General of the U.S. Army decreed that suppressors are a part of military equipment. Be that as it may, suppressors can be acquired by paying a $200 federal transfer tax and going through all the Form 4 paperwork associated with NFA weapons.

Or, better yet, make one at home. Dr. Dater told the class about experiments with seized and home-made suppressors that he performed with properly calibrated sound equipment at the California Criminalists Institute. First came the oil filter, nothing more than a common, everyday oil filter fitted to the end of a Ruger 10/22. “That one worked pretty well,” Dr. Dater laughed. “We got a 22 decibel reduction.” He tried a sprinkler head with a wadded up piece of cloth inside, a 2 liter pop bottle, a tennis ball can of three balls and, the best of all, a potato. “The potato worked really well, probably because of the high water content, but the bullet came out with what I’d guess was 30 degrees of yaw. Very unstable,” Dr. Dater said.

How Suppressors Work

The reason why potatoes and tennis ball cans don’t work so well is because they’re not addressing the three ways in which a suppressor works. First, a suppressor decreases pressure by increasing volume so that a bullet driven down the rifling of a barrel exits the muzzle into a tube of (ideally) 20 times the volume of the gun’s bore. Second, the tube serves as a heat sink to lower the temperature of the propellant gases, again serving to lower pressure. Third, the internal system of baffles in a suppressor tube serves to create turbulence to delay the exit of propellant gases, again allowing for more heat transfer and volume expansion.

When the bullet leaves a suppressor, just as it would from an unsuppressed muzzle, an “uncorking event” occurs. An uncorking event is the appropriately named term for what happens when a balloon bursts or a champagne cork pops. It’s the sudden release of pressure, the uncorking of the projectile exiting the muzzle crown, which makes a gunshot as loud as it is.

All suppressors rely on these three factors to work. However, there are two main types of suppressors. We’re most familiar with the muzzle suppressor, a pipe-like device that attaches to the end of a barrel but there is also a category of integral suppressors in which the barrel itself is totally enclosed within a shroud.

With an integral suppressor, the barrel is vented with holes to bleed gases into the shroud, which serves to suck away heat, increase volume and stir up turbulence. A good example of an integral suppressor is HK’s MP5 SD. Several companies make Ruger 10/22s with integral suppressors. The advantage is you’re not adding any length to the barrel; a disadvantage is you’re losing a lot of velocity and thereby giving up considerable terminal ballistic performance, plus you can never remove the suppressor. Integral suppressors are generally quieter than muzzle suppressors.

Additionally, a suppressor can be “wet” or “dry” meaning that an ablative agent, usually water or grease, is used within the can to further decrease sound. Dr. Dater noted that some unscrupulous manufacturers rig their testing by pouring water into a dry can to enhance its performance.

Baffle Stacks

All cans look pretty much alike from the outside: a piece of hollow tube. Granted, there’s a lot of engineering in the tube with calculations based on the pressure of the propellant gases to determine the material (steel, titanium, inconel, aluminum) for the tube and its wall thickness. Factors such as hoop stress and yield stress are figured as well.

But tube construction is really not what separates different designs. The baffle stack – the shape and arrangement of a set of washer-like constrictions within the tube – are what make one design work better than another.

Baffles are certainly not new. Hiram Maxim used them. Your car’s muffler uses them. The K-baffle, so named for its cross-sectional shape, was developed in 1909. It features a large surface area for heat dissipation and achieves increased turbulence for “frequency shifting” by acting like the closed end of a whistle or pipe organ. “Frequency shifting” is a phenomenon whereby a sound wave is reflected back on itself to cancel some of the energy, like swirling your hands in a bathtub in opposite directions.

The M-baffle is another type, also named for its shape in cross-section. There’s a coned baffle and a pinched cone baffle. There are concave and convex baffles. There are slant baffles and mysterious sounding Omega baffles. No one type is inherently superior and, Dr. Dater told the class candidly, of the six different brands of suppressors he routinely uses in testing, any one of them can show the most decibels of sound reduction on any given day. “There’s a lot of atmospheric variation,” he says.

So far Dr. Dater has focused on the technology used to suppress the sound of a gunshot, but what if there is no sound to suppress? The idea of silencing the cartridge, not the gun, has long been a focus of Soviet suppressor technology and is called captive piston technology.

Instead of a propellant igniting to create pressure to push a bullet down a rifled barrel, a captive pistol cartridge retains the propellant in a chamber that pushes a piston into the base of the bullet. The “sound” of the propellant igniting is contained within the combustion chamber of the cartridge so it never escapes into the atmosphere.

In practice, a Soviet SP4 captive piston cartridge generates 124.6 dB, which is about what an integrally suppressed Ruger Mk II .22 LR pistol creates.

At The Range

Dr. Dater set up his sound testing equipment at the Desert Hills Shooting Club in nearby Boulder City to demonstrate the theory he’d explained to us with real guns and real suppressors. He started by showing us how Mil-Std 147 4D calls for the microphone to be placed 1 meter to the left of the muzzle, 90 degrees to the bore.

The sound testing equipment itself is highly specialized. The microphone is an LD2530 that’s been certified to a “rise time” of no more than 5 microseconds. The rise time is the time from the start of an event to the beginning of the microphone recording the event – think of it as “response time.”

The microphone is about the size of a pencil eraser and costs $1,000 a copy. It’s connected to a Larson-Davis 800B Type 2 sound pressure meter that in turn is calibrated to a rise time of 20 microseconds. Before any actual sound testing can begin, the unit must be calibrated with another device that produces exactly 400 Hz at 114 dB.

Without this type of precision equipment being properly calibrated and set in accordance with Mil-Std 1474D, any test data is invalid. Some suppressor manufacturers simply concoct “data” from thin air without making any valid tests at all, picking a number that makes their products look good against the competition. Dr. Dater derides such unscrupulous business practices as “specmanship,” the use of fabricated specifications to enhance a flawed product.

As the testing begins, the class experiences firsthand a phenomenon called “first round pop” in which the first round fired registers a higher decibel level than subsequent rounds. This is due to a secondary detonation within the suppressor from superheated, incompletely burned powder entering an oxygen-rich atmosphere. After that “first round pop,” the oxygen is burned off, so subsequent rounds register normally.

The next phenomenon we see in action is how suppressors increase the cyclic rate of full-auto weapons by as much as 200 rounds per minute. This is because the baffle stack in the suppressor delays the gas exit and therefore increases gas pressure back through the gun’s gas port. ARs are known to “run hot” with a suppressor to the degree that gas blow-back through the charging handle can sting the shooter’s eyes, even with eye protection. Accordingly, it’s a good idea to run a PRI “gas buster” charging handle on suppressed ARs.

When the numbers start coming in, we see that sound levels are far more consistent than muzzle velocities. As a longtime handloader, I’m used to chronographing loads that vary as much as 200 feet per second, a significant amount, but the decibel levels from all the guns we’re testing are remarkably consistent. Less than two or three decibels variation isn’t unusual.

The other thing we note is that different brands of 5.56mm suppressors show very little variation. For instance, a Knight’s Armaments M4 QD, SureFire 556K, Gemtech G5 and Advanced Armament M4-2000 were all so close – around 135 dB – that any difference would be statistically irrelevant. We’re talking less than 3 dB difference from the “best” to “worst.”

Which brings us to an important point: suppressor brands shouldn’t be judged solely on their sound reduction. What’s more important are their method of attachment and their point-of-impact shift. Additionally, the dynamics of a weapon are altered substantially with a suppressor making the gun more muzzle heavy, slower to transition between targets and harder to manipulate in close confines. Some brands over-hang the muzzle more than others.

As we shot various weapons – rifles, subguns, pistols, World War II era Welrods, even a pistol used in a murder – several things became clear:

• For pure performance, you can’t beat a .22 LR. The ratio of suppressor volume to bore diameter makes the little rimfire ideal to suppress, along with its low noise signature to start with.
• Suppressors are the world’s best muzzle brakes. Recoil is virtually eliminated.
• Suppressors are great for the guy who hates to clean guns. Dr. Dater says a suppressor should never be cleaned.
• You can minimize the gunshot – the uncorking – but you can’t get rid of the sound from a bolt slamming home or the sonic crack of a bullet. Yes, even suppressed guns make a noise. (The bolt of an M4 slapping home to an empty chamber registers 117 dB.)
• You can’t effectively suppress a shotgun; No Country For Old Men notwithstanding. There’s no safe way to allow the shot column to pass through a baffle stack.

Dr. Dater’s class is a fascinating addition to any tactical shooter’s knowledge base. It’s a classic example of “You don’t know what you don’t know” until you get there and take the highly informative class. For more information, log on to www.longmountain.com.

“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).