Greggory, Felons remain barred from possessing modern firearms under federal law but can use black powder, muzzle-loading guns. The key is to check your local State Law as they sometimes override Federal Law which is bass ackwards. Some states do define black powder and/or antique guns as "firearms" for purpose of felon-in-possession. So a felon would need to check their local laws in detail before purchasing. Some very helpful info here : -- jobsforfelonshub.com/can-felons-muzzleloader/

Greggory, No problem having your buddy use a black powder firearm even as a felon. I have a buddy in CA, convicted felon. Carries every day a black powder revolver and has black powder long guns. No issues.

I'd look into bow hunting as well. It takes a bit more skill to get something with a bow, but could be a viable option.