ORIGINAL: cayugad
With that twist I would say a roundball and patch would be good. But a person I know actually shoots one of them rifles. He thinks its something to do with the rifling, but he CLAIMS that it will shoot 245 grain aero tip powerbelts with 80 grains of powder so well, that it is what he hunts with. He said, he's never lost a deer with that load.
I am sure it would shoot maxiball, maybe even some Great Plains Conicals... and for fun, shoot roundball. All you can really do is try.
like dave, ROUNDBALL is fun,thats all i shoot for practice.
i use 70 grs of 2f with .490 ball /.018 patch/bore buttonwith hoppes bp in winter on patchand bore butter in summer.
370 MAXI-BALLS shoot real good not the awful MAXI-HUNTERS AT 80 GRS.