Several years ago, I bought a Bushmaster Varmint series rifle chambered in .223. That rifle gave me headaches from the start. It was short cycling, and about half the time it would not eject the spend case. I sent it back to Bushmaster 3 (Three) times, and each time they said their repair department fired a full magazine through it without any problems. I finally came to terms with the fact that Bushmaster employs bafoons and gave up. My second AR purchase was a Smith & Wesson M&P15. That rifle fires like a dream. It will cycle old corroded ammo as well as top end cartridges without a hiccup. Anything I fire through that rifle punches a 3/4" group at 100 yards. I would like to buy another AR, but I keep wondering if the great performance of the Smith AR I bought was a fluke or the standard? I know I don't want to buy a Bushmaster, because their repair technicians are sub-par at best. I would like to hear some of your opinions on AR rifles. Is there a particular manufacturer that is known for producing rifles that are more reliable than everybody else? What I want is a rifle that will print groups under 1" at 100 yards that will also cycle both cheap and expensive ammo. When the shtf, you have to use whatever ammo is available at the time, so I want a rifle that will cycle everything...including cartridges that are not loaded to maximum pressures and green corroded junk. What say you?