Sure! DPMS makes some and you might be able to find other manufacturers that also offer them. Traditionally, the AR-15 and similar fire NATO 5.56mm which is very similar to Remington .223. The AR-10 fires a 7.62x51 (.308) round which might be more to your liking. It is functionally similar to the AR15 but heavier, of course.
I have a both a Stag Arms in 5.56 / .233 and a Barrett in 6.8. The 6.8 is awesome but it's hard to find ammo for and it's expensive when you do find it. The ballistics on the 6.8 are outstanding though! It has great knock down power and superior accuracy to that of the 5.56 / .223.
Let me see if I can remember them all.. On a standard 5.56 lower, with an upper change you can get: .50 Beowolf 450 Bushmaster (just released) 6.5 Grendel (awesome long range round0 6.8 SPC (mentioned above) 7.62x39 9mm .45ACP .300 Whisper That should be close to most of them.
Forgot one or two of my favorites, .22 LR and .22 WMR. I understand there is someone making .17 rim uppers now also...
You forgot: .458 SOCOM .24 Ghengis (5.45x39 with a different name) .499 Leitner-Wise And you need to get a dedicated lower to shoot the .45ACP
Let's stick to 'SAMMI' rounds here! You are making my head hurt... Anyone remember the .222 AR's from the factory? I used to smack ground hogs with them WAY back... -------- My .45 upper does NOT need a dedicated lower. I know the ones using some of the double stack mags do.
Yeah, those .222's were for countries like in South America where citizens cannot own anything made is a military caliber. Ruger sold a lot of Mini-14's down there in that caliber. -Bidah
The 7.62 X 39 round does not like the strait mag well of the AR15 overly well. The AR47 setup works because it uses unmodified AK mags. I have also seen AR's .204 Ruger too.
AR in 7.62x39mm with AR-47 lower that accepts AK mags and drums. Fun to shoot and real cheap. I like this thing because most of it's parts interchange with my standard AR's and it makes a great light .30 standoff weapon.
