Any suggestion on what powder to use in this gun? I have tried Triple Seven Pellets, Pyrodex Pellets and Shockey's Gold powder, all 100 gms., using power belt bullets, and sabots. All with the same results, after the first shot it's very hard to load again. The fouling at the beech end is very hard and crusty. I have run a patch down before shooting, tried bore butter but it’s is very hard to get the load down to the original mark on the rod.
Sounds like your barrel may be a bit undersize, some are over and some are under, I have one that I had to go with a Mini Lee mold and make my own.
as the powder goes off it spreads the "skirt" at the bottom of the mini
and grabs the grooves and lands. Super easy to load, just enough to keep it from falling out of the rifle barrel. I tumble mine in Lee liquid Alox and use Bore butter to stop lead from building up.
I go to a local (State Steel) scrap yard for pure lead. it is only about .27
cents a pound and I just use a Coleman camping stove and an old lead melting pot. I make ingots with a Lyman ingot maker, they are about a pound each.
this has worked fine for me for over 15 years, up to and a bit beyond
100 yards it is plenty accurate.