10" barreled XP100's hit 5" claybirds, 200m

QUITE routinely. The AR's well proven to shoot JUST as well as its BARREL can. Many xp's are very close to .5 MOA, and a shorty AR can be, too. It's just a question of having a good enough barrel, and fitting it to the upper receiver in a manner suited to creating match guns. A scope, on a rifle, is MUCH better able to extract ALL the accuracy a barrel has to offer than is any pistol, scoped or not. A 10" AR-15 can be set up to pull head shots, most of the time, anyway, at 300 yds, and stay on the chest at 400 yds, dumbasses. Not that there's any reason to bother doing so, but only MORONS would bet much that it can't be done.