Bill - you should always use real black powder in a muzzleloader. The phony powders don't work worth jack crap in a flinter & mix the phoney powder's fouling with msoe moisture from the air and you have changed to fouling to an acid. It's your gun. The phoney ones also greatly increase the shot to shot velocity, usually producing poorer accuracy.

All of my advice on loading and shooting has been for black powder only - not the subs.