The Bison is a brass framed gun so IMO, it should be shot with round balls and moderate to light powder loads only.
Bass Pro Bison LINK
Steel frame pistols can be shot with either round balls or bullets. The bullets must be made out of pure lead, not alloyed lead like modern pistol bullets.
Folks who want to shoot bullets either have to cast their own with special molds, or buy them from suppliers like Dixie Gunworks.
From what I've read, the round balls shoot more accuratly than the bullets but the bullets carry more energy.
Many states do not allow hunting deer sized animals with cap and ball pistols.
There are IMO, several reasons for this.
First, because of the limits of the chamber size, the maximum powder loads are very limited.
Second, most blackpowder hunts are designed for single shot firearms so the multishot design of the revolver keeps it from qualifying.
Could you kill a deer with one? At close range, with a well placed shot it would be capable of success but the same could be said for a .22 magnum.
As a side note concerning the Bass Pro information, not the posts question, I always thought Wyatt Earps Buntline was a long barreled Colt .45 cartridge gun. Little did I know he shot a Brass Framed Remington with target sights. :rotf: :grin: :rotf: