I deer hunt with a .308 (DPMS LR-308). Doesn't directly apply to the original question, as the AR-15 frame doesn't support .308, but it is relevant to the discussion of destroying deer with gut-shot and otherwise shot up spray and pray hunting. Every deer I've taken, and they have all been taken with a semi-auto, was one shot one kill. Clean heart shots except for two, one was lung shot, one was head shot. I've never gut shot a deer. And yes, an AR style rifle can be plenty accurate.