I shoot an old TC Tree Hawk percussion cap 12 gauge muzzle loading shot gun. This gun is screw in choke compatible. I use a Carlson XR Longbeard choke in it. The TC thread are the same as Winchester/Mossberg threads.
I only pattern to 27 yards. I don't field hunt and must of my shots are within that distance.
My original load was:
90 grains Goex BP
Lubed fiber wad
BPI TPS 12 gauge 2 3/4 shot cup.
110 grains measure volume of copper plated 6 shot.
Topped with another lubed fiber wad.
This load shot very well. The pattern was even and all most all of the shot stayed in a basketball sized circle.
This year I started using #9 TSS. The pattern is dense, but maybe a little bigger than a basketball.
My need step is to try to buffer the TSS. With this slightly wider pattern, I could possible start getting pellets in the breast meat.