I shoot a T/C Firestorm flinter. Once I chopped that #$%%*& QLA (Quick Load Accurizer) off and made a false muzzle out of polyethylene it shot much better. I'm not sure why everyone wants to get to the top end of the powder spectrum... it's a lot more fun and quieter to work near the low end unless you're stopping a grizz. I work at about 60 grains of 777. I use a .490 ball and patch, and around 300 grain conicals. Since the "lopping off" I better groups from the conicals than patched balls. I haven't used sabots after my first bout with the rifle. The groups were terrible. As too max loads, a lot of muzzle stuffers are proofed up to 150 grains. A much braver (and tougher) friend of mine tried 120 grains in my flinter,,, but he only shot it once. His reaction..... OUCH!!