I've got an H3 in the 16" 7.62x39.

It ran OK with a standard buffer, but I could definitely feel it hitting the back of the extension tube. The H3 smoothed it out real nice.



Another reason I went to the H3 in the 7.62 was because I figured delaying the unlocking a bit, should help reduce or eliminate the chance of losing a bolt lug. Apparently that has happened with the 7.62x39 in the AR.