Luckily for me my 42" Rice barrel wasn't picky as far as powder goes. I have to shoot pretty heavy charges to get the best accuracy. I use 115 grains of goex 2f or 1 1/2 swiss with a .024 pillow ticking patch and a .570 ball. Both powders shoot the same point of impact in my rifle. Groups were a little better with the goex though. I had to reduce the charge with 2f swiss to 105 grains to keep the same point of impact. Your mileage may vary.