I'd like to know what other calibers(Not 308) are offered in the AR15 style rifle.  Make or brand doesn't matter, but I'd like some input if you have a "unique" caliber.  How about any 204Ruger??

Are there any semi-autos in 204Ruger?  How about 50 caliber?  Is this too strong for the action and receiver? (Not bolt action, but semi-auto).   Didn't I see a 300 in an AR15?

Thanks,(senile) Dave  

A few that come to mind, I'm sure there are others.

458 SOCOM
204 Ruger
20 Tactical
475 Tremor
338 Spectre
500 Phantom
17 Remington
6x45
6.5 Grendel
6.8 Rem SPC
300-221
30 HRT
357 Auto
223 WSSM
243 WSSM
25 WSSM

Thanks Parrandero,  Do you happen to know of a few brands(of the rifle) in these calibers?
Are all of these of the AR15 style AND semi-auto?




Not so senile anymore, Dave