H110 and 296 are the most common powders to push the heavy bullets in 454 Casull. And the 460 is faster, but similar. My brother has killed moose, grizzly, and Dall ram with his .454s. But most Alaskans I know carry their pistols for bear protection, rather than as their hunting weapon.
Most load heavier hard cast lead bullets for deep penetration on large bears. They don't expand, but with the semi-wad cutter flat-faced designs, they still prove lethal, plowing through bones and all else.
300gr on up would be common for bear protection loads. I load 335gr hard cast gas check bullets for my .454, but I don't hunt with it. A local man stopped a large old charging boar brown bear with 360gr bullets from his Ruger Alaskan .454. Make sure to tightly crimp the bullets. This guy's revolver jammed after his killing shot because his bullets jumped their crimps. Had the revolver jammed one shot prior, he'd be dead.
For smaller game, expanding bullets would probably be fine. For large bears at close range, heavy hard cast semi-wad cutter bullets are most common and recommended.