RE: CMMG 22LR conversion bolt

[choochoo]

I recently got the CMMG 22LR conversion bolt. It works great, spit out everything I fed it, cheap Fed bulk 36gr, CCI standard, CCI mini-mag, CCI velocitor, CCI AR22, Eley Target, Eley Club, Eley Force.

I didn't really get a chance to test the accuracy, it's coming out of a 16" 556 1/7 barrel. But, I'm not expecting much out of this combo.

The one issue I had was that I was getting blowback of some sort of debris in my face, no matter the ammo. I couldn't tell if it was that I put too much lube on the slide or something else. Anyone have this experience? It's rather annoying.

sorry for the crappy picture

[chomorro]

I have the same problem with my conversion. It can actually burn my cheek sometimes if I get too crazy with the trigger finger. I use it on a 10.5 ar pistol and it runs fantastic.

I have not found a solution for it yet but I was thinking a rubber shell deflector may help. I have one but havent tried it yet because I was using the gun for competitions.



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[TRAP55]

I just finished cleaning and repairing one that came as a complete dedicated .22 upper. I haven't had "hands on" with the conversion in a 5.56 upper, but it makes me wonder if you're still getting gas back through the port, or is that blocked with the conversion?

[chomorro]

I just finished cleaning and repairing one that came as a complete dedicated .22 upper. I haven't had "hands on" with the conversion in a 5.56 upper, but it makes me wonder if you're still getting gas back through the port, or is that blocked with the conversion?

I think it's powder burn through the ejection port but I could be wrong.


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[TRAP55]

The gas coming from the tube would exit there, is what I was getting at. The CMG bcg is blowback, so it would open a split second before the gas exited the tube. That's my best guess.

[Garand Hunter]

I have a CMMG conversion in a Rock River upper on a Superior lower and have not experienced this issue. Neither Winchester nor CCI Mini mags do it. Maybe someone out there can enlighten you.

Psalm 1

[choochoo]

The gas coming from the tube would exit there, is what I was getting at. The CMG bcg is blowback, so it would open a split second before the gas exited the tube. That's my best guess.

Maybe I should try blocking the gas port or removing the gas tube, since this is a dedicated 22 upper anyways. (yes, I know I have a 556 barrel.... long story =D)

I have a CMMG conversion in a Rock River upper on a Superior lower and have not experienced this issue. Neither Winchester nor CCI Mini mags do it. Maybe someone out there can enlighten you.

Psalm 1

Have you noticed that the lower is much dirtier? I noticed on mine that there was a bunch of powder residue in the lower.

[chomorro]

Hmmm well I do have an adjustable gas block. I guess for a test I could block it completely and see what happens. Seems like it would work

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[therealnickb]

Hmmm well I do have an adjustable gas block. I guess for a test I could block it completely and see what happens. Seems like it would work

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[choochoo]

Hmmm well I do have an adjustable gas block. I guess for a test I could block it completely and see what happens. Seems like it would work

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Let us know how that works out.

[lgm118icbm]

Normal. On their dedicated uppers, the standard dust cover is shortened to make room for a large deflector that blocks the blowback.

I think I might even have one lying around if you want to try it. I'm in Costa Mesa.

[chomorro]

Normal. On their dedicated uppers, the standard dust cover is shortened to make room for a large deflector that blocks the blowback.

I think I might even have one lying around if you want to try it. I'm in Costa Mesa.

Wow never noticed that. Here it's one that can be added on https://www.brownells.com/rifle-part...prod71265.aspx

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[choochoo]

damn.... my upper doesn't have the dust cover....

[therealnickb]

damn.... my upper doesn't have the dust cover....

[oktavist]

It could also be coming through at the charging handle. They make charging handles with gas deflector ridges on them. Good safety feature in general and an easier install than switching to an adjustable gas block.