Gemtech’s Mossad Uzi Silencer

By Al Paulson

The Vector Arms Uzi clone is certainly one of the most attractive values in automatic weapons available to the Class 3 community today. This weapon begs for a sound suppressor to enhance the shooting experience, to safeguard the hearing of the shooter and nearby observers, and to open up shooting venues where the noise pollution produced by full-auto fire would otherwise be objectionable. Such a suppressor should be robust, compact, mount in such a way that it does not loosen from the torque and heat generated by full-auto fire, and provide plenty of sound suppression to both protect operator hearing and keep noise pollution to a graceful level. For the armed professional using an Uzi operationally, the suppressor should protect the operator from both short-term and long-term hearing loss, even in confined spaces (what you can’t hear can kill you), provide enough sound suppression to maintain verbal communication among team members, and provide enough sound suppression to hide the fact that a shot has been fired when used with subsonic ammunition. Gemtech designed a single sound suppressor for the Uzi that satisfies this ambitious multi-user wish list: the Mossad.

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.


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).

This article first appeared in Small Arms Review V5N11 (August 2002)
and was posted online on January 10, 2014


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