Have you tried a .50 MINIE (they DO cast them.) in your barrels?
It's NO secret on this forum that I'm a FAN of 2 different calibers:
1. .36 cal., so that I can use PRB (000 Buck) for small (tree rats, bunnies, etc.) and "medium small" (foxes, coons, possums, etc.) game AND for targets, all year
AND
2. .58 PRB for WT and HEAVY (over 500 grains) Minies for TOUGHER to STOP game.
(Like BIG hogs & TX Exotics, which grow faster/bigger/tougher here than they do on their "home range".= "Blue Bulls" really do grow >100 POUNDS bigger here than in India!).
just my OPINIONS, satx