Originally Posted by Glockcurmudgeon
AR type rifles have only a few that can operate with full caliber ammo. The new LMT 7.62X51 adopted by the Brits is one. Knight Armaments has another. Both are on the AR platform, and both use pistons. HOWEVER, they are not as robust as the PTR, which is a modern build, like they are...
IF you must have an AR platform, LMT and Knight are the best- PERIOD.
A little late to notice this I admit. But Armalites all handle full power 308 ammo quite well. At least mine has through it's first 2,000 rounds of near flawless shooting. much of it Hornady TAP. I found some Federal hunting rounds don't have enough umph to cycle the action correctly so I stick with Hornady. Thing loves the 110gr TAP round in fact and is a tack driver. In fact Armalite really were the first to the show commercially. I have an LMT 5.56 and they are truly fine weapons. I'd love one of their AR10 variants but the Armalites are a bit cheaper to buy, and easier to come by.
Seems like lots of folks are hung up on the initial cost of magazines. Who really cares about the price of a magazine? High functionality and reliability are my first priorities, not cost. If I can't afford $30 mags, I really don't need the gun in the first place. Two or three boxes of ammo will cost more than that mag will, if you shoot 308.