I've shot my Staghorn w/100gr 777 and 240 & 300 gr sabots. None hurt as bad as a 12ga slug. In fact... I was at the range with my CVA Buckhorn the other day - the one that didn't blow up - the most I loaded it with was 90gr Pyrodex & 289gr bullets, and some 385gr conicals with 80gr pyrodex. While letting the barrel cool, I shot a few KO slugs out of my 870 with a rifled barrel, and they hurt a LOT more than anything out of the muzzleloader. I think you'd have to put 100+gr 777 behind a heavy conical, to boot you as hard as a 12GA Brenneke.