Nice shooting... Them GM barrels are sure shooters. Mine liked 90 grains of Goex 2f and a .530 speer ball with a .018 moosemilk patch.

I had the same barrel and discovered I had only shot mine 30 times. A friend has a T/C Hawkins .54 that he kind of messed the barrel up do to taking a stupid pill after hunting season. So, I sold it to him. Needless to say he is pleased. And I really do not miss it.