I think it takes some sort of banded bullet. I wonder though if it would shoot a solid conical design. A custom mold won't be cheap. Perhaps you could try the old Lyman minie ball for thr 69 caliber musket. I would try to cut the noses to remove weight. Then you can test it. You could also try using a 20 gauge slug in a Ballistic products BP12 wad for a sabot. Good luck Greg