something from IMR3031 to Varget and R15 and anything at all in between. Much slower along with the op rod is liable to finding bent through the port pressure timing. 4064 is actually a fav. In my M14 rifles I utilize it and 4895 and AA2530 as well. I generally retain the R15 for my M40 bolt rifles. "I won't be wronged, I won't be insulted, and I