I like 3f, for main charge and prime. Here's some really old charge weight rules of thumb...For rifles, half the weight of the ball is a sensible starting load. But every once in a while a .50, or even a .45 turns up that just shoots alot better with 2f, then the charge should be closer to twice the caliber. Rifles can be finickier than women sometimes! I also draw the 2f to 3f line at 58 caliber. In older guns, especially muskets with their thinner barrels, the lower pressure of the 2f is a definate advantage. The big bores won't foul as bad as the smaller ones with the coarser powder, so you can just use more, and still keep the pressure lower.
