"2F in rifles and fowlers,3F in pistols" I like a .535 RB,.015 - .020 patch,spit(real wet),and I would start at 70gr. of 2F. If your barrel twist is less than 1 in 66",say 1 in 72", I'd start a little higher,80+- 2f? add to adjust. Mine liked 75gr. I'll bet that 90grs.of 2f is where you'll end up. Should be enough power for moose, elk, bear, deer, & targets!