AR uppers, Interchangability of calibers?

civiliansoldier

Hey everyone. I would like to get uppers for my ar in different callibers. Can anyone tell me the different calibers I can use on my stock Bushmaster A2 lower assembly? I wish I could go with .308, but I am pretty sure it requires a different lower reciever. Thanks for the input everyone.[:)]

Mooseyard

These are all ones I have seen for the regular AR lower, .17 Rem,.204,50 Beowolf,.499 LW, WSSM, and I'm sure more. I just can't think of any.

cce1302

you need an AR-10 lower for .308.
from sskindustries.com, these all can be chambered in an AR-15 upper.
17 Remington
20 Tactical
204 Ruger
221 Fireball
222 Remington
222 Rem Magnum
223 Remington
6/223
6 MM PPC (JDJ)
6 MM Whisper
6.5 Grendel
6.5 MPC
6.5 MM PPC (JDJ)
6.5 MM Whisper
7 MM TCU
7 MM Whisper
300 Whisper
458 SOCOM

I'd like one of each, please.

Nwcid

Basically any round that is short enough to fit in the mag can be chamber in the AR.
If you get into the AR10's you can shoot anything .308 or shorter.

HandgunHTR52

I think that the 6.8 SPC can be used with the AR-15 lower as well.

agostino

As can these WSSM's: .223, .243, and .25.

agostino

Also, don't forget .50 Beowulf, 7.62X39, and 5.45X39.

BHAVIN

50 BMG. With the one I am familiar with the A.L.S. you will have to put in a new trigger and hammer but other than that you are good to go.

Mk 19

Don't forget the:
6mm AR (http://www.6mmbr.com/gunweek068.html)
6.5 Grendel
450 Bushmaster
50 American Eagle

tsr1965

Then there are the pistol calibers too. They use a special magazine, but I have seen them in 9mm, 40S&W, 10mm, and 45ACP.

cce1302

forgot about .22lr.

Okay, now who can name a caliber you can't chamber in an AR?