405 gr. Lee hard cast or WWt quenched will drive for 'bear' deep penetration, which I hear is what you want for bear (Ive never hunted bear), and Blackies are one thing, Griz another.
If you are using for whitetail the .459ish wont need to expand, so a hard bullet can pass through and still let out a lot of wind and vital fluids. You will have to make sure that whatever you use, either cast by you or commercial, is of the right diameter for your rifles throat.
FWIW, I mostly use WWt's, and range scrap (garagealloy), unquenched. You can easily mix into that soft lead up to 50/50 is you want something to expand some.