Gemtech GM-22 Rimfire Suppressor for Awesome Plinking Fun

A large part of the appeal of suppressors, besides the “We couldn’t have them before” is quiet. And the quieter, the better. What do you get when you team a quiet suppressor with an already-quiet cartridge? A metric boatload of fun. Which brings me to the Gemtech GM-22. With a weight of a mere two-and-a-half ounces, the GM-22 has to be close to a record-setter for fun-to-weight ratio. At a suggested price of $399, that ratio also has to be near the top. Combine it with the low cost of rimfire ammo (relatively speaking, despite the staggering cost of ammo these days) and you have to have pegged the meter for fun. When I teamed the GM-22 up with the Buck Mark Gold, the fun meter was definitely pegged, as I giggled more than once.

Read Patrick Sweeney's complete review of the Browning Buckmark Gold Here

The GM-22 is one of the new designs of suppressors, called a unicore. OK, a bit of historical back-tracking. The usual, traditional way to make a suppressor was to take a seamless tube, weld a rear cap or mount to it, stuff if full of baffles, and then put a front cap on it. In the case of centerfire rifles, all this was welded shut, as they never need cleaning. Rimfire and pistol suppressors, however need cleaning. Let me take a moment and be clear: you must clean your pistol and rimfire suppressors after use. Even a day of shooting can get them caked with powder residue and bullet material. Failing to clean them means they will soon be “welded” shut by the debris, and get heavier and heavier, and louder and louder. Once that happens, it takes exploratory surgery to get them open. Don’t be that guy.

The drawbacks are clear: you have to wrestle individual baffles, which can be relatively fragile, out of the residue-packed tube. Clean them, then re-install them. Also, the serial numbered tube, with its permanently attached mount, is the registered part, and if you break or mangle it, you have a delicate repair process coming up. The unicore design solves a bunch of those problems. The center, the baffle design, is a single machined piece. Gemtech starts with a rod of 7075-T6 aluminum, and after boring a clearance hole down the center, and turning it to diameter, starts machining out the center. The machining creates baffles, but these are not delicate. And they do not have to be removed from the tube one at a time. The rear of the machined core has a thread set inserted in the base. This thread set is CNC lathe-turned out of titanium, so it is as light as the rest of the suppressor, but tougher than aluminum. You are, after all, threading the suppressor onto a steel barrel, and aluminum threads on a steel barrel are not a good mix. Titanium on steel is stronger, much stronger.

On the outside base of the core, Gemtech threads it for the sleeve. Yep, the suppressor, the serial-numbered part, is simply an aluminum sleeve that threads onto the unicore. As a manufacturing process, this has several benefits. The unicore has all the complicated machining. That means it is all done on one machine, and the precision a suppressor needs can easily be maintained. The sleeve is so dead-simple it is almost insulting to a modern CNC machine to be used for the cutting, but it makes the task a cinch. It also means that the serial-numbered part is one that requires little if any handling or cleaning, and thus greatly reduces the risk of damage. You can go your whole life without mangling a suppressor part, but if you do, and it is the complicated, serialed part, then you have to return it, with the requisite paperwork, for repairs. With a unicore system, and the tube simple, if you mangle the unicore, you can send it for repair or replacement, as it is just parts. It isn’t serial numbered.

Now, the design does pose some interesting situations. I won’t call them predicaments, but you do have to know what you’re in for. You install the GM-22 the same way as all others; remove the thread protector (if any) and screw on the GM-22. Removing it is the delicate part. If you simply grab the GM-22 and unscrew it, you are as likely to be unscrewing the tube from the unicore as you are removing the GM-22 from the host firearm. Notice that the base of the unicore is a bit wider than the tube? And that it has some scallops on its border? You need to be grabbing there when you go to remove the GM-22 from the barrel. Do that, and you’re set.

Cleaning the GM-22 is also easier. Since you don’t have a handful of loose baffles to juggle, you can simply fire up your ultrasonic cleaner, filled with an aluminum-appropriate solution, and let it go. Or, use brushes and solvent to scour the nooks and crannies clean. The tube itself needs little, just a scrubbing with a brush inside, a hosing with solvent, and a little lube.

When it comes to suppressors, I have heard from the makers that the rimfires are by far the most popular. No-one will give actual numbers (not even to me) but the ratios I have heard run from two-to-one for rimfires versus all centerfires, to ten to one. Given the cost and fun factor, that should not be surprising. Testing the GM-22 was uneventful, but fun. The main predicament with unicores is that they tend to have a bigger “first round pop” than more traditional designs. This is due to the oxygen in the tube allowing continued combustion. With the first shot using up the oxygen, the subsequent shots are quieter, as the gases can’t combust. I noticed the GM-22 sometimes gave a louder report on the first shot, and sometimes not, which is typical of all the unicore-based suppressors I’ve tested. Whatever is going on, it isn’t as simple as “oxygen in the room” as described.

Read Patrick Sweeney's complete review of the Browning Buckmark Gold Here

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On the Buck mark (and I suspect, on any other host firearm) the GM-22 did not shift point of impact. Granted, that is with two-inch groups at 25 yards, but really, if I can’t see a shift in a group that sized with a handgun, how much shift could there be? A half-inch? A quarter-inch? If there was any, it didn’t matter, so I’m saying “no shift.” As far as quiet, well, this is the apex of quiet. A handgun is going to be noisier than a rifle, simply because the uncorking is at a higher pressure, and the suppressor has more to handle. If you want truly “hollywood” quiet, you have to go with a rifle, and better yet, a bolt-action rifle. But out of the Buck Mark, it was quiet. The Gemtech GM-22 comes in a cardboard box, with a FDE carry pouch, an instruction sheet, and the promise of fun to come.

I know some of you are looking at the price and thinking to yourselves “Wait a minute, I’m expected to pay a $200 transfer tax of a four-hundred-dollar suppressor? What’s up with that?” what’s up is that the tax isn’t a percentage of the MSRP, and thank goodness no one thought to index it to inflation back in 1934. (If they had, it would be four grand today.) This is America, we can have fun, and fun costs, and the cost of the tax is the same regardless. The waiting time starts only once you submit an application, and doesn’t get any shorter just because you grumble about it. So, get going, and get ready to have fun.

Gemtech GM-22 Specs

• Type: Rimfire-rated suppressor
• Construction: Aluminum
• Length: 5 in. 
• Width: 1 in. 
• Weight: 2.7 oz. 
• Threaded: 1/2x28
• Sound Reduction: 36-39 Db
• Contact: Gemtech

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About the Author

Patrick Sweeney is a life-long shooter, with more than half a century of trigger time, four decades of reloading, 25 years of competition (4 IPSC World Shoots, 50 USPSA Nationals, 500+ club matches, and 18 Pin Shoots, as well as Masters, Steel Challenge and Handgunner Shootoff entries). He spent two decades as a professional gunsmith, and two decades as the President of his gun club. A State-Certified law Enforcement Firearms Instructor, he is also a Court-recognized Expert Witness. 

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