I have read a few posts about bump-firing, and a few people are of the opinion that an AR can't be bump-fired very well due to the light recoil. Well, today at the range I dumped a few mags of XM193 and Q3131A using the bump fire method. It was AWESOME! The XM193 did a little better, but both worked fine. What a kick!
I will admit that my AK still tops my AR when it comes to ease of bump-firing.