Gemtech's Outback .22 Rimfire Suppressor

By Al Paulson

Some suppressors are designed to be the M1A1 Abrams tanks of their division, delivering peerless performance, extraordinary toughness, and a price to match. Some are designed for minimal price, while performance and sometimes durability may be secondary factors. And some look for that elusive middle ground - the mythical “sweet spot” in sound suppressor design - that delivers a good compromise between sound suppression, weight, durability, cost of materials, cost of fabrication, and economies of scale. Gemtech has found a sweet spot with their Outback.

I evaluated Gemtech’s Outback silencer on the Walther P22 pistol for several reasons. This snazzy little pistol has clearly taken the States by storm. And fully a year before the release of the P22, Gemtech and Walther USA (now Walther America) began working together on a solution for suppressing that would become the hottest selling .22 LR pistol to appear in recent years. The result was Gemtech’s steel suppressor adapter, which features 1/2x28 TPI threads on the stepped up muzzle end, and an exact replica of the Walther’s barrel nut on the barrel end. The Gemtech adapter replaces the factory barrel nut using the wrench that comes with the pistol. Changeover is fast and easy. The Gemtech adapter is blued to match the pistol and comes standard with a beautifully knurled thread protector, at a retail price of $60 directly from Gemtech.

The Gemtech adapter has become an authorized factory accessory, and it’s even available with the P22 Walther logo from Earl’s Repair. Walther GmbH in Germany now uses Gemtech silencer adapters for their own in-house pistols. The Gemtech adapter works with both short and long P22 variants. The shorter P22 is preferred for adding a sound suppressor, since it will keep high velocity ammunition subsonic, even with the freebore boost typically generated by a sound suppressor. It is interesting to note that Gemtech actually began advertising the Walther P22 before Walther USA got its own ad campaign rolling. The success of Gemtech’s ad campaign showing a P22 with Outback silencer really helped kick-start interest in the P22. More than 30,000 P22s flew off dealers’ shelves in the first year, making both the Walther P22 and the Gemtech Outback major commercial successes.

Walther P22

The Walther P22 is a straight blowback, SA/DA .22 rimfire pistol, which at first glance resembles a downsized version of the 9x19mm Walther P99. Key features includes a light polymer frame, easily interchangeable 87 mm (3.43-inch) or 127 mm (5.0-inch) target barrels, adjustable three-dot sighting system, optional scope mount, ambidextrous safety and magazine release, loaded chamber indicator, firing pin safety, magazine disconnect safety, and interchangeable rear grip panels to fit differently sized hands. The P22 magazine holds 10 rounds, and the Walther comes with a pair of magazines.

The P22 employs a conventional SA/DA trigger, which releases a conventional external hammer. On the P22 evaluated in this study, single-action trigger travel is about 0.2-inch, and the trigger breaks at about 4.4 pounds (factory specs suggest 4.85 pounds). Double-action trigger travel is about 0.6-inch, and the trigger breaks at about 11.2 pounds (factory specs suggest 12.35 pounds). Unlike most SA/DA pistols, the P22’s safety merely serves as a hammer block rather than as a safety/decocker. The hammer can still be dropped when pulling the trigger, but it won’t reach the firing pin.

This makes dry firing this .22 rimfire practical, which I find a most welcome feature for using this pistol in beginning pistol safety and marksmanship classes. Using a suppressor on the pistol facilitates instruction, the maintenance of safe gun handling practices, and shooter comfort. The students can clearly hear all instructions and range commands, and Gemtech’s Outback is more effective at safeguarding short-term and long-term hearing than conventional shooting muffs or those designed specifically for youngsters.

The P22’s polymer frame features an alloy trigger housing with steel trigger components. The aluminum slide features a steel breechblock that is pinned in place. As a sign of the times, the right side of the frame just above the frame has a tiny keyhole for a trigger lock. Just don’t forget or lose the little key if you elect to use this feature.

Gemtech’s goal was to develop a .22 rimfire silencer that could deliver respectable sound suppression: perhaps within 5 dB or so of high-end silencers that may be longer, heavier, and cost up to twice as much. A key to reaching this goal was fabricating an all aluminum sound suppressor. Even the threaded mount is aluminum. This is the one design aspect of this excellent suppressor that may be open to debate. Since debates in the silencer field sometimes generate more heat than light, it is worth exploring both sides of the aluminum thread debate as part of the hands-on evaluation of the Outback sound suppressor.

Aluminum Thread Debate

I’ve seen a number of sound suppressors featuring aluminum threads that had been destroyed. Some were ruined by ham-fisted individuals who over-torqued the cans on threaded barrels. Others - particularly in .45 ACP and centerfire rifle caliber - had their aluminum threads battered by the hammering of combustion gases trying to drive the silencers forward with every shot. I certainly understand the argument against aluminum threads.

Kel Whelan, director of government sales at Gemtech, makes an interesting counter-argument in favor of using aluminum threads for suppressors of rimfire and pistol caliber. “My standard answer on the subject of thread material,” Whelan began, “and one that I think deserves a fair shake as an opposing argument in the periodicals, is that ALL threads can be damaged under abuse. I sold literally hundreds of Outbacks, and have yet to see one come back for repair of threads. In, I believe, the six years the aluminum Vortex-9 has been out on the market, with duty use in many a police armory, and in government testing from Alaska to Afghanistan, we have repaired a total of FOUR damaged [rear] end caps.

“If aluminum threads are abused by threading on the wrong way,” Whelan continued, “or if the threads are abused by over-tightening, they will strip. However, if stainless threads are abused in the same manner, they will not strip. They will gall. Galling, or the seizing of steel-on-steel contact, can ruin not only the end cap, but also the barrel itself. The question an end-user has to ask if he expects abuse is, ‘Would you rather damage an expensive barrel, or an easily replaced end cap?’”

I understand Gemtech’s point of view, and they make a good argument. What’s my own point of view? I certainly believe that stainless or chrome moly steel threads will indeed last longer than aluminum threads. Nevertheless, I’ve achieved 16 years of intermittent service out of an all-aluminum .22 suppressor with no end of service life in sight. This European suppressor is crafted out the lowest grades of aluminum I’ve ever seen in a sound suppressor. The aluminum blast baffle is eroding from sandblasting by particulates in the combustion gases, but the threads are holding up. Gemtech uses superior metallurgy in the Outback, so I would expect at least comparable longevity to my old European can, if used as often and handled with the same level of care. If you’re concerned about this issue, consider Gemtech’s all stainless steel Vortex-2 sound suppressor, which measures 0.96x5.1 inches, weighs 7 ounces, and retails for $499. That said, theoretical thread life is not the only issue here.

The Outback (which is the same size as the Vortex-2 and is based upon its technology) weighs just 3 ounces and retails for $299. That’s roughly half the weight and price of its stainless steel sibling. The Outback features 1/2x28 TPI threading and a nonreflective black anodized finish. Threaded adapters are available to mate the suppressor to 3/8x24 TPI barrels common to compact pistols, and threaded barrel bushings are available to replace the Walther P22 factory bushing.

Both the aluminum Outback and steel Vortex-2 suppressors are equally at home on rifles. But the ultralight Outback really shows its user-friendly comportment on polymer-framed pistols such as the Ruger 22/45 and Walther P22. Balance of the all-aluminum Outback on these pistols is nothing short of outstanding. Even if one wanted the Vortex-2 as a robust working tool and family heirloom for the generations, there would still be a compelling case (budget willing) to also own an Outback for the Walther P22 or Ruger 22/45, since the these lightweight pistols and suppressor are so well suited to each other.

The original design goal for the Outback was to achieve a sweet spot in sound suppressor design that delivers a good compromise between sound suppression, durability, and price. The one factor in the overall performance equation yet to be discussed is sound suppression.

Outback Performance

I tested the performance of Gemtech’s Outback sound suppressor on a Walther P22 with 3.4-inch barrel using three kinds of Remington .22 Long Rifle ammunition: 40-grain RN high velocity (HV), 40-grain RN standard velocity (SV), and 38-grain HP subsonic (SS). Suppressed performance was compared to an unsuppressed Walther P22. All pistol and suppressor combinations were tested on the same day at a temperature of 54 degrees Fahrenheit. The speed of sound was 1,111 fps. This study employed the testing regimen and equipment used by Paulson (1996) as amended by Paulson, Parker, and Kokalis (2002), which are available from Wideworld for $50 and $49, respectively, plus $5 s&h (check or MO only). All test data appear in the accompanying table.

Note that even with high velocity ammunition, the Outback delivers airgun performance of 121 decibels. Compare that sound signature with a Crossman American Classic Model 1377 .177 caliber air pistol, which delivers sound pressure levels of 120-123 dB, depending upon the number of pumps. The Outback delivered 120 dB of gunshot noise with standard velocity and 118 dB with subsonic ammunition. The latter is better than pellet gun performance out of a noisy short-barreled pistol. Looked at another way, the Outback delivered 35 dB net sound reduction across the board with all kinds of ammo. That’s very respectable performance out of a dry can. Furthermore, the Outback’s net sound reduction comes within 5 dB of Holy Grail territory - 40 dB of net sound reduction by a dry sound suppressor.

Subjectively, the Walther P22 with Outback silencer was a pleasure to shoot without hearing protection. Folks inside my house who were engaged in normal activities did not even notice when I shot the pistol in the backyard. The suppressed P22 also handled very well during rapid-action drills. Reliability was flawless. This was a pleasant surprise, since early reports indicated that the Walther P22 was unreliable with some kinds of ammunition, even with some high velocity variants. The system evaluated in this study was reliable with every variety of ammunition used in the study, as well as with a wide variety of odds and ends fed to it on subsequent range days. Newly designed magazines, and a proper break-in period, probably contribute to the enhanced reliability. Accuracy was surprisingly good from a short-barreled .22 pistol fired from sandbags, delivering three-shot groups ranging from 2.2 to 2.9 inches at 25 yards with all ammunition types used in this study. The pistol performed best with standard velocity target ammunition.

Holsters are still hard to find. The Don Hume leather holster for the KelTec P40 fits well even though the ejection port depression is in the wrong place (Order Number H720-OT-40FS), but there is no place to store the extra magazine or Outback. Gemtech recommends Uncle Mike’s UM Ambidextrous Hip Holster with magazine pouch (Number 70050 in Size 5). The magazine pouch can be used to store the Outback sound suppressor.

What’s the bottom line? Gemtech’s original design goal for the Outback was to achieve a sweet spot in sound suppressor design that delivers a good value at a good price. The Outback is affordable, lightweight, and airgun quiet. While it provides excellent service on .22 rifles, I find the Outback to be a particularly attractive addition to a polymer-framed pistol. Gemtech found a sweet spot with their Outback sound suppressor.

Literature Cited

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

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


Dept. SAR
P.O. Box 140618
Boise, ID 83714
Phone 208-939-7222
Fax 208-939-7804
Website www.gem-tech.com

Walther America
Dept. SAR
2100 Roosevelt Avenue
Springfield, MA 01102-2208
Phone 800-372-6454
Fax 413-747-3682

Dept. SAR
P.O. Box 1827
Conway, AR 72033

This article first appeared in Small Arms Review V6N11 (August 2003)
and was posted online on October 25, 2013


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