I find it difficult to comprehend that it would be hard to find a factory load that would be bad for deer and bears since the 454 has killed all the major game of the world.
Me, I would buy a couple boxes of the Cor-Bon 300 gr loads or 335 gr loads and sight in and go hunting. It really isn't rocket science. Maybe a box of Hornady 300 gr XTP loads or some from Grizzly Ammo or somewhere.
I assume that since cape buffalo and rhino have been killed by the 454 deer and bear wold be no problem.