When i got a new AR last fall, I was shooting some wolf millitary classic ammo through it, because it only costs four dollars and change. Accuracy was just fine at 50 yards (plinking off the back porch of the farmhouse), and on thanksgiving we were passing it around and fired about 200 rounds in an hour or two; no problems, but nothing really demanding either. Then I read on the internet, how wolf ammo was actually a communist plot to make all the ar's malfunction so Russia could invade us easier.
I asked my armorer about this, and he said Russia wasn't communist anymore. He also said that wolf ammo wasn't covered in the same type of sticky stuff it used to be covered in. His assesment was that it wasn't match-grade or as powerful as the $7 stuff (federal lake city xm193), and that the coating might cause trouble in very demanding conditions like a zombie attack; but that the main problem he had actually seen was that the harder steel case would wear out the extractor sooner than brass would, and that this equally applied to hornady or other steel cased ammo.
So I decided to stock up on the lake city stuff, since zombie preparedness was ostensibly my reason for buying the rifle anyway.