I used to shoot cast bullets for jack rabbits, hogs and deer. I loaded it at upper end 45-70 level and it worked just like a 45-70. The Sierras would usually open on a deer and there are several newer bullets that would be worth a try. The Woodleighs designed for 45-70 or old express cartridges would be a natural fit. Same with bullets designed for the 454 Casull. Lot's of possibilities.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli