There's no question that the 405-grain will give better penetration if it's a 500-pounder, the angle is poor and heavy bone is hit. IMO, you also want an exit for the sake of blood letting. Heavy bears carry a lot of fat in the fall - up to 4 inches and this will close up an entrance wound and even an exit wound of a smaller caliber than your choice.
I've shot several bears with .458" slugs from 400-grain jacketed to 465-grain hardcast. I'd go with the heavier bullet every time. Now that you have the 405gr Woodleigh, go with it! Otherwise I'd recommend the plain-jane 405 Remington. I've used it at 2100 fps on bear and you won't find them. They will pass thru a bear from almost any angle. But, as already stated above, a heavy hardcast will do the same. My last bear was shot with a 465-grain hardcast at 1900 fps from a NEF 45-70 and it was flattened in its tracks.
Right now I'm loaded for bear with the 350gr TSX in .458" in my Ruger No.1, 45-70 Improved at 2400 fps and my CZ550 in 458 Win at 2700+fps.
