.22 LR Supporessor Question

[Squeeze]

I am looking into getting the Gemtech GM-22 suppressor. It will be going on my AR pistol using the CMMG 22 LR conversion kit. My question is will there be any issues with baffle strikes since the barrel is technically a 5.56? My understanding is .22 LR is closer to .57 than .56 anyway. Just want to make sure before I invest in a suppressor that won't work on that platform.

Thanks in advance.

[FireMoth]

So, couple of issues.

Yes, it can work... but...

The .22lr is usually actually .221"-.222".
5.56x45mm bullets are .224"
The dichotomy in size isnt all, as .22lr is slower and generally much lighter, leading to a common twist rate of 1:16 (vs 1:7-1:9 in your AR barrel).
What this means is that improperly stabilized bullets could partially shred. Though damaging baffle strikes are rare, you can pack your can with lead frag and even partial bullets, making it hard to clean and limiting performance.
This can also mean crazy erratic accuracy.
Finally, you'll have to direct thread the can on the 5.56 barrel, which needs a spacer, and may preclude the muzzle device you normally use from being properly torqued on.
Worst case, you forget to change the muzzle device back on, and find out what happens when 5.56 gas volume hits a .22lr can.
...
You're gonna spend good money on the can, plus 200 on the tax stamp, do a lot of paperwork, and wait a long time.
For all that, why take a risk? A dedicated .22lr upper (correct bore diameter and twist rate, with no 5.56 risk) or a dedicated .22lr rifle (a m&p 15-22 with moe-sl furniture and an mlok free float handguard is $450) are a cheap investment to preserve the life of your can, and enjoy it's full performance.

[Little Dutch]

To reiterate what FireMoth said; you could, but I wouldn’t recommend it.

Conversion kits don’t necessarily stabilize the converted cartridge because the barrel twist didn’t change. That *might* lead to a baffle strike.

your .223 can is probably sealed. Not a big deal, but shooting a lot of .22s through it will fill it up with crud.

I would not be concerned about occasionally shooting .22’s through a sealed .223 suppressor. So long as it was from a dedicated .22 pistol or rifle.

lots of local guys are making $150 to $200 monocore .22lr suppressors. And you can form 1 a .22 for the same cost (or less) without the wait.

[Hoser]

The GM-22 is a solid rimfire can but there are better and quieter options out there. Gemtech was bought out recently and customer service is poor to shitty anymore from all reports.

Seeing as how you can take apart the GM-22, have fun and shoot it.

I have shot buttloads of 22 rimfire through a centerfire 223/5.56 barrel. Accuracy was so-so, but all the bullets were stable and I never once saw a keyhole. As noted above, a dedicated rimfire barrel is the best option.

[Circuits]

Probably tens of thousands of rounds through a 5.56 barrel with my conversion kit and a cheap can, with no problems.

If your bore is concentric to the barrel threads, there's usually not a problem, though the points made above about crud, leading, and possible bullet fragment collection are valid if your particular barrel doesn't shoot 22lr stably or its threads aren't properly concentric to the bore.

Out of a 1:12 older barrel, accuracy is verging on excellent, and it's been good enough to ring flip targets at whim in the 25-50yd range from my 1:9 barrel. I haven't tried it in a 1:7, though.

[Squeeze]

You guys rock. I was thinking the same thing Rob mentioned above. Not entirely excited about paying the $$$ for a commercial can & waiting 10 - 14 months to get the stamp back just to incur problems. I simply built the AR pistol as something for my youngest to plink with until he's ready to move up to 5.56. I have built 2 other cans on a Form 1 and considered just doing that since it would be significantly cheaper and easier to do. Might just go that route. I appreciate all of your input guys.