I have to agree with stealhead, bigger dia moderate moving bullets seem to a job on blackies, I have seen many black bears run after a good shot from a 30cal like 308/3006 using a 150-180gr bullet and run like nothing hit them,unless you head shoot them, but when you hit them with a big dia like a .458 400gr at 1800fps they just fold, drop where they stand, as long as the shot placement is good. Interesting how that works, I would think something traveling around 2400fps using a 180gr bullet would be much more devastating than a .458 400gr at 1800fps, bottom line is the proof of the pudding, Big dia's moderate speeds on bears work the best, I would not believe it till I have seen results from baited bear hunters, I guess the big dia bullet of course makes a bigger hole and in tern bleeds them out quick, lowering the blood pressure of the bear at a higher rate than a smaller 30cal bullets. Aim small hit small. RAMbo.