In 1974, my chronograph and I found 4064 for my 20" BLR. Nothing else available then could shoot faster or tighter. It was also the only one with a pressure curve that allows me to work the lever almost like the Rifleman. If I told you how it shot, we'd have to listen to all the disbelievers moaning, crying and ridiculing others to make up for their inabilities, so we won't do that. Over the years, its still come out on top in 4 other bolt guns and another BLR. Start at 44gr, then depending on your bullet, chamber, throat, cases, hairstyle, cologne, whatever, in half grain steps, ease up to 46gr absolute max. I'd try other powders, but I just got lazy and quit looking.