I'll say M16, fairly easy to use intil it jams, which sucks when you go with friends to the gun range with an AR-15 (semi-auto M16) and it starts jamming, bad surplus ammo. I've used a .357, you know you've fired that. I like the Steyr though as well, saw one in a store and it felt good, but M16 all the way, a rifle doesn't stay in action 40 years if it isn't worth using, just remember to clean it.