Another age old question, IMHO, the 556 is a great indoor rifle, and on open territory, will take down big animals, but when your target is concealed, or just behind substantial cover, will not deliver, that's when the .308 shines or even 762x39 does a much better job. Sometimes 1 is too much, another, not enough, but in the end, my .308 and my 762x39 will come with, probably my .556 as well, as it is next to me in the bedroom and easiest to grab.