Quote Originally Posted by Dave View Post
.450 Bushmaster, .458 SOCOM and .50 Beowolf are all fine cartridges for 200 yards and less and you'll stay in the AR-15 platform. Anything more than that and you'll want to up it to an AR-10 which can be chambered for calibers from .243 Win to .338 LM. A good .308 WIN AR-10 that you can hunt with will run you more than a bolt gun, but can be configured to other uses.
Can't do .338LM in an AR-10/LR-308.

You can do .338 Federal, .338 Whisper, etc, but Lapua requires a long action.