Black bear hides are not very thick and their ribs aren't that tuff either. But you need to put whatever head you use behind the shoulde blade. It will stop most heads cold. A friend of mine uses Rocket Hammerheads, 3 blade mechanical with a 2" dia. cut. He gets some easy blood trails to follow. The big hole helps because the bears fur will soak up a lot of blood.

I killed my only Black Bear with a 4 Blade, 90 gr. Muzzy. It zipped thru so fast the bear never knew it was shot. It just backed down the tree and started to walk away. Only made it 10 yards from the tree and fell over dead. And I got it on video too.