I got 3F, was a little taken aback by the velocities they were quoting in rifles. I guess the stuff is safe in rifles. I might back off the charge from my normal 90 grains, though, if I try it in the Hawken. I bought it for the revolvers, though, and specifically hope it juices up the little .31 a few FPS. The thing is in the 700 fps range with pyrodex and the 60 grainers. I'm noping I can get it in the 800s, anyway. Don't wanna push it TOO hard, owing to the brass frame, but it's only a .31 after all, has the Remington top strap for strength, and I think it can take it. I may back off the charge for shooting, but I wanna see what it's capable of with the 777.