I was given an old 50 Cal Thompson Hawken from a friend that cam from an estate. The rifle is missing the rod and stock retaining pin. and not in very good shape but salvageable. The hammer won't set but I believe I can fix that. The problem is it has a stuck projectile in the gun. Removed the nipple and got most of the powder out but can't seam to get a ball puller into the whatever kind of bullet that is loaded. Tried one of those co2 air cartridges but it won't budge. Any suggestions as what do do next?