Be aware.........when I loaded for my AR, NONE of the rounds would fully chamber in the gun! This led to some pretty frustrating moments in the field, let me tell you.
I bought two items that solved the problem: A case gauge to check the assembled ammo, and a SMALL BASE DIE. I had been using brand new RCBS dies but evidently my gun has a rather tight chamber. I ended up pulling about 500 bullets after checking the rounds in the gauge, and resizing the cases with the small base die. Using those two tools gave me reliable feeding and peace of mind.