Oh yeah - I could hunt happily with that rifle - moose and bear and of course, deer, caribou, elk - you name it.
: With round ball, the case should hold 100gr. to 110gr. 2F, with an Oxyoke lubed wad beneath the ball. While the powder charges are a bit soft of the charge I'd use in a flintlock muzzleloading rifle, it would suffice in the ctg. gun, without vent pressure loss. The round ball will probably be the most acurate as the twist rate is probably better suited to round ball than slug. If the twist is measured at 48" or faster, either will work. The extra weight of powder with round ball over factory loaded ammo with slug should help replace the recoil generated by the factory load - helping with regulation. It may even hold 120gr.2F - the more the merrier for trajectory and penetration. Too, WW alloy balls could be used for even greater penetration. This would become an excellent non-dangerous game rifle, with bears included.
: My buddies did good work indeed with cloth patched round balls in their 12 bore shotshells - so this also is a consideration for the Snider or smoothbore as the case may be - that is, an undersized ball, cloth patched to take up the windage. In this case, a card wad should be beneath the patched ball to protect the powder from becoming wet from the patch. Hoppe's #9 PLUS is about as good as anything for this use. Note #9 "PLUS". This is a BP solvent. Nitro solvents don't soften nor mix with black powder residue and therefore foul badly. If using one of he fakes, it's up to you, I have little experience with these but still used BP solvents for lube.