22lr m4 upper build...

[pkuptruck]

so, I got the notion to build a 22llr upper. I have an old Air Force conversion unit ( CMMG copied this style.. )
and dont really care to send lead down my barrel.


finding 223 or 5.56 or 300BO barrels is stupid easy. And cheap.

But a 22lr barrel seems to be more of a challenge, unless it is a pre-build dedicated upper..

Anyone do what I am attempting to do? Any success? Ideas?

thanks!

[jmonarch]

Midway has a couple. The seem a little pricey to me. https://www.midwayusa.com/product/32...hamber-adapter


ETA : I just went with a pre-built dedicated upper.

[Remo]

https://www.righttobear.com/CMMG-dro...-SS-s/1873.htm


$125 for cmmg 16" 22lr barrel

(But doesn't have the chamber collar like the one at midway)
Which looks to be something that is needed to go from conversion kit to dedicated upper. Looks like you just take out the collar with the smoothbore extension and replace directly with the short collar that the dedicate barrel would set in.

I'm wondering if the smoothbore extension can be removed from the collar then that collar be used?

[Moleman-]

A dedicated 22lr upper is on my list of things to do. I have a M261 (Army) kit that it minute of tin can but isn't as accurate as I'd like. A buddy of mine gave me one of the CMMG barrel collars so I figured I'd get a CMMG kit and either make a barrel or get one.

[Remo]

That's next on my list also, dedicated rifle for .22lr. I'm starting from scratch on an 80% lower.

[pkuptruck]

https://www.righttobear.com/CMMG-dro...-SS-s/1873.htm


$125 for cmmg 16" 22lr barrel

(But doesn't have the chamber collar like the one at midway)
Which looks to be something that is needed to go from conversion kit to dedicated upper. Looks like you just take out the collar with the smoothbore extension and replace directly with the short collar that the dedicate barrel would set in.

I'm wondering if the smoothbore extension can be removed from the collar then that collar be used?

so, what exactly does the collar do? ( am am old .. and a little slow.. lol)
what is different from the 22lr barrel and chamber, than say a 300BO, or 5.56 ?

[Roundballer]

so, what exactly does the collar do? ( am am old .. and a little slow.. lol)
what is different from the 22lr barrel and chamber, than say a 300BO, or 5.56 ?

It is not so much the chamber, but the round (rimmed vs non) and the action type (locking vs straight blow back).

[Moleman-]

The collar has the feed ramp in it and also acts as the front end of the 22lr bolt group. On the non dedicated uppers the "collar" is called the barrel and the front section has the same basic profile up to the neck area of a 223/556 case. I was looking at modifying the CMMG collar I have to fit my M261 kit, but it looks like I'd be better off just getting a CMMG kit when they're on sale at some point. As a stop gap measure I've made a couple more 9mm uppers for the kids to use since 9mm can be reloaded pretty cheap compared to 223.