My first AR was a 5.56 just like most here. It was an A1 version and I really like shooting it but it had a non removable carry handle and I never saw a hog while I had it out. Then there was a parade of Flat top AR's all in 5.56 that I did use for night hunting feral hogs. I shot more than a few with the Federal XM193 round and with the right hits it was pretty good at killing hogs. That said I lost more than a few also. I built an upper with a 20 inch barrel 1x7 twist and tried the heavier bullets, what I found was that unless I made a solid CNS hit most of the time that hog would make it 75 yards at least into the dark and amongst the thorns where looking for a hurt hog in the dark isn't all that smart so eventually after a couple of real thrills I quit doing it. One exception to the CNS hit it seemed to me if I hit the heart solidly the hog seldom went far. Best load I used in the 5.56 was the 75 gr. Hornady BTHP on top of a max amount of IMR 4895. In my opinion the 5.56 is just not as good as bigger guns like the 6.5 Grendel/6.8 and not even close to the 7x57 or 308 no matter what you load it with.