Hi Al-

Do some web-searching on the .62 caliber muzzle loader.
There are lots of guys out there running '20 gauge' smooth bore guns with roundball - and doing quite well with them on game.

I haven't killed any big game with my 20-bore rifle yet, or I'd happily share with you my experiences with it on meat and bone.

I'm sure Daryl will cruise along here shortly.

Cheers
Tinker