The tool you want to buy for measuring brass & setting up your die is an RCBS Precision Mic; I usually set the brass to it's fired size minus .003" for any specific gun. If sizing for non-specific gun & ammo to be used in any gun, I size to min HS dimension (zero on the Precision Mic; Go-gauge dimension) minus .003-.004".
With 69, 75 & 77 gr bullets, my preferred powder is AR-Comp with MR-2000 & XBR-8208 as a very close second; all flow much better than Varget or RL-15, but those are good choices as well. For lighter bullets, I'll use the 8208 or H4895 for the most part.
No real need in most cases for a small base die, but if you have it, use it.
MM
