Anything from IMR3031 to Varget and R15 and something in between. A lot slower and also the op rod is at risk of finding bent with the port pressure timing. 4064 is really a fav. In my M14 rifles I use it and 4895 and AA2530 as well. I normally hold the R15 for my M40 bolt rifles. I'd much WC844 (H335) and a great deal of loaded in the event the c