CMMG 16in 22LR Barrel

[burnup4ag]

Hey guys. I'm building a dedicated 22LR AR-15 and I just received my 16in CMMG 22LR Barrel from Brownells for 189.99. After assembling my upper, I noticed the barrel sits more back into the receiver and it looks like the barrel's overall length is less than 16 inches installed. My main concern is do I need to pin/weld a muzzle break since it looks shorter? What are the legalities? I search around and can't get a straight answer (centerfire vs rimfire). Any help is greatly appreciated!

[Grumpyoldretiredcop]

No pinned/welded muzzle break needed. Barrel length is measured from the breech face to the muzzle (flash hider/brake removed or its length discounted unless pinned or welded). ATF describes a simple measurement method on their website; using a dowel that will fit in the bore, drop it down the barrel until it contacts the bolt face of the closed bolt. Mark the dowel at the muzzle (excluding non pinned/welded muzzle devices). The measurement from the end of the dowel to the mark will be the barrel length. Barrel length requirements are the same for either centerfire or rimfire. In this case, the design of the rimfire barrel and its bolt assembly allows the barrel to seat deeper into the upper receiver than a centerfire barrel would. It's still a 16" barrel.

Your main concern is making sure that your completed rifle meets the overall length requirements (26 inches in the shortest fireable configuration, IIRC). If you are assembling a dedicated rimfire AR using standard collapsible buttstock components, you should have no problem with this.

[burnup4ag]

Thank you very much for the clarification. I can now finish this without any worries.

[AR22]

Yep, your fine. Put up a photo of the project when you get it done.

[G21Shooter]

Your good to go, thats normal for .22 lr AR barrels.

Also you can run a flash hider, putting a muzzle break on a .22 lr is a little silly.

[burnup4ag]

Haha, I did put a flash hider on. Anyways it's complete and I shot it today. I must say, I'm rather impressed with the CMMG conversion kit and barrel . I shot it with Federal Automatch/Champion (Bulk Ammo), Standard American Eagle, and Standard Remington without any hiccups. Only problem I had was the CMMG bolt open adapter likes to work when it feels like it. I already ordered the Better-Mag adapter and S&W mags to replace the standard one.

[AR22]

Great move using the Better Mag and the SW mags. The Last Shot Bolt Hold Open will work flawlessly with that setup.

The CMMG LSHO device and evolution mags are joke. CMMG makes some really nice dedicated .22 stuff. Mags stink..

It looks great.

[burnup4ag]

Thanks! Seriously, I cannot wait for my better-mag adapter and s&w mags. The cmmg mag sucks to load.

[AR22]

Yes the SW ones are a dream to load..