Kaiser,
Welcome to the forum by the way!
fstdraw,
I have a similar AR-15 to the one you mention. For range fodder or the kind that you may need a lot of in a hurry type, I use BL-C(2) and have had great success with bullets in the 55gr range. I load right in the middle of the published data because I have some military brass. The brass is thicker leaving less room inside for powder.
It is a great combination. I was using Varget for my heavier loads. When I got my Dillon XL650 though, the powder would "slosh" out when it indexed because the cases are so full. With the finer ball powder, that doesn't happen. It meters like a dream too.
I have shot some pretty amazing groups at 100yrds with mine. Hope it works that well for you!