Gemtech's Alpine & G5-22 Silencers
By John Titsworth, Jr., Silencer Research LLC

Consumer demand for user serviceable .22 LR silencers is at an all time high and Gemtech revealed two brand new .22 LR silencers at the 2010 Shot Show in Las Vegas. In this study, the Alpine and the G5-22 as well as the Outback II were tested. The Outback II was used as a reference as its one of the most popular, best selling silencers on the market today. In order to bring the reader the broadest possible spectrum for these silencers, three pistols and four rifles were used in testing. The pistols include the Walther P22, the SIG Mosquito and the Ruger MKIII with Tactical Solutions Pac-Lite upper. The four rifles used were the CZ-452, M&P15-22, Ruger 10/22, and Colt M4 with 16 inch barrel with Atchison conversion.

Facts and Myths about .22 LR silencers

It was once widely believed that user serviceable or "take down" design silencers were many decibels louder than their sealed brethren. Recent testing has shown that this is merely a myth as two of the top three .22 LR silencers tested on a pistol were take down designs. Take down designs also took the top 3 on a Ruger 10/22 as well. It was also believed that sealed up silencers never got louder as they clogged up. One school of thought was they actually got quieter when dirty. This is all nonsense and has been proven false. Each time a .22 LR round is fired, a tiny amount of molten lead and carbon adheres itself to the baffle stack, and over time the baffles simply become clogged up and cannot function properly. Much as is the case with a muffler on an automobile. Silencers that are sealed do get louder with use and if used enough will require a rebuild by the manufacturer. Host weapon, barrel length, rate of fire and other factors will dictate how fast a silencer will become clogged up and lose efficiency. Pistol and rifle use on a sealed silencer will usually allow between 10 and 15 thousand rounds to be fired before cleaning is necessary, but use on a .22 LR machine gun will cut round count to one third. I would never recommend using a sealed silencer on a .22 LR machine gun.

Gemtech Alpine

The Gemtech Alpine is manufactured from 7075 series aluminum and is hard coat anodized. The thread insert is titanium to help prevent galling. Weighing in at only 3.7 ounces one hardly notices the weight on a pistol and it's nearly impossible to detect when used on a rifle. It doesn't occlude the factory sights on any of the pistols tested. One of the best features of this silencer is the fact that the powder gas (which generates molten lead and carbon deposits) is not allowed to reach the outer tube. This is an ingenious design feature that makes disassembly of the silencer much easier than traditional K baffle silencers. Few other silencers on the market offer this feature. The silencer can be disassembled with a U.S. coin and a wooden dowel. I personally used a plastic writing pen to push out the stack. Reassembly after cleaning was a snap. Instructions are provided with the silencer including drawings.

Gemtech G5-22

This silencer was created to allow the end user to get the same look as a 5.56mm rated G5 on the new, popular .22 caliber AR-15 look-a-likes, such as the M&P15-22, GSG AK-47 and a number of others. The silencer comes with one quick attach mount and you can purchase others. It works exactly as the Bi-Lock does on the full sized G5. The silencer is 7075 aluminum hard coat anodized and can be disassembled for cleaning by the end user. A tool is supplied but is not required in a pinch. I disassembled the silencer without the tool without any trouble. If you don't like the look of a 1-inch silencer on your AR-15 conversion or one of the new AR-15 .22's then the G5-22 is a great option.

Sound Testing the Silencers

Sound testing was conducted with two Bruel & Kjaer 2209 impulse sound meters equipped with Bruel & Kjaer 4136 1/4 inch condenser microphones and calibrated with a Bruel & Kjaer 4220 pistonphone. Testing was done at two locations as per Mil-Std 1474D. One microphone was placed 15cm from the shooter's left ear and one was placed at what is known as the "reference" location which is 1 meter to the left of the weapon's muzzle, 1.6 meters over the ground. The reference location is more commonly used in silencer testing.br>
Host Weapons Testedbr>
The Walther P22 has become the gold standard in silencer testing in recent years as it is readily available and can be adapted to accept a silencer cheaply and quickly. Adapters that fit the already threaded factory barrel are available for around $40, which represents less than half the price of a custom threaded barrel. The Ruger MKIII is a bit more pricey, but I really enjoy the feel of the weapon when equipped with the Tactical Solutions Pac Lite threaded 4.5 inch barrel. The Pac Lite is a super accurate upgrade to any Ruger pistol. The SIG Mosquito can also be adapted to accept a silencer with the correct adapter. While the Mosquito has had mixed reviews from users, I have had no problems from the weapon. The Ruger 10/22 is also the gold standard of silencer testing as they are so popular and one can either have a factory barrel threaded or one can buy any number of pre-threaded aftermarket barrels that are accurate. In this study, I used a factory barrel that I threaded. The CZ-452 is a very nice traditional bolt action .22 LR host weapon. This particular one was factory threaded and with the use of an inexpensive adapter you can affix your silencer right away. The Colt M4 used for this test has a 16 inch barreled upper and I used a drop in conversion kit that is available from a number of sources including Ceiner, CMMG, and others. The magazine used in the Colt M4 was the reliable Black Dog Machine plastic magazine designed to work with the conversion and it even has a bolt hold open feature. The M&P15-22 was also tested as the G5-22 was developed to fit this type of weapon. I threaded the barrel on this weapon myself. It needs to be understood that the general industry standard in the USA for .22 LR silencers regarding barrel thread length is around .4000". Many factory threaded barrels that are being offered today use the .6000"+ thread length that is for flash hiders. This creates a situation that allows the silencer to be screwed to far onto the host weapon's barrel and the barrel becomes dangerously close to the first baffle. This can seriously damage the silencer and the crown on the barrel. It is therefore highly recommended that you use a spacer to alleviate this problem when using barrels that are threaded beyond .4000". These spacers are available from a number of sources, including www.thesilencerstore.com.br>
Final Impressionsbr>
At the reference location using the Walther P22 and the Ruger 10/22, the Outback II and Alpine produce virtually an identical sound signature. At the ear, the Outback II sounds quieter as shown in the charts. The G5-22 is quieter on the M4 with the Atchison conversion kit at the reference location than the M&P15-22 is. However at the ear the meter shows there is no discernible difference as one decibel is required for the human ear to notice a difference. I did find it interesting to show that the CZ-452 was considerably quieter at the ear than the Ruger 10/22 showing a near 8dB difference. I believe Gemtech has hit a home run with the new user serviceable .22 LR units and I think they offer excellent sound reduction for anyone looking for a quality .22 unit.

This article first appeared in Small Arms Review V14N8 (May 2011)
and was posted online on November 1, 2011


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