Upper and lower compatability

[elchucko]

Are any of the 22 cal AR/M4 carbines capable of switching their 22 cal upper with a centerfire upper? This includes S&W HK, Mossberg and all the others. I've gotten various opinions on the subject.

[Microgunner]

There are some. The CMMG, the Spike's Tactical, the DPMS (I think) and I'm pretty sure there are others will accept centerfire uppers.

Many of the better AR-15 22s are built on standard AR-15 lowers and will accept centerfire uppers.

S&W, HK, Mossberg, SIG, Chiappa, Colt (among others) will not accept centerfire uppers.

[elchucko]

You state "many of the better AR-12 22s" will accept centerfire uppers. Too bad Colt isn't on the list. I like the 22 cal Colt M4 OPS I have but shame on me, I should have done more research on the subject. I don't have a need for a centerfire upper but it would be nice to have that capability. It's just more of the idea of having a "real" AR platform as opposed to a gun that looks to be one but really isn't.  I'll make admission. I bought my Colt from Wal*Mart. I know the associate very well and he's the owner of 7 AR centerfires(for what reason I don't know). Anyhow he claims to have swapped uppers on the Colt  and S&W and they "fit". He was not able to actually fire them. And of course you can't return guns to W*M. As I stated before, I like the Colt but.......

[Microgunner]

The S&W utilizes standard AR-15 trigger groups so as far as the hammer striking the centerfire firing pin if a centerfire upper were installed is possible but I'm fairly sure that S&W has made it impossible to install a centerfire upper on their AR-15-22.

The Colt, SIG & Mossberg have nothing inside that remotely resembles an AR-15's innards and I have no doubt that a centerfire conversion is impossible.