Gotta get into this FWIW. After researching this topic for years I've determined that in order to try and avoid getting chewed, scuffed, or killed, one would have to disrupt the CNS of a PO'd grizz. It's not so much how big and fast the bullet is. Rather it's placing a bullet that will do the job in the right place. I believe the right place is in one of it's eyes, or between them. we're talking about a 4-500 pound critter that can cover 50 yards in 4 seconds. If the first shot doesn't go right you better be able to recover and get off another. A former commercial bullet caster told me that a 400-grain WFN around 20 brinnell traveling 1000 fps will penetrate more bear than necessary. The gun I carry is a .480 Raging Bull with a 5" barrel (built-in brake). My load just breaks 1K, and is pretty easy to control. I practice a LOT on getting it into action. I'm nowhere near where I want to be, but I'm a lot better than I was when I started. I'm thinking about possibly getting a 10 mm auto just because they are lighter. Any gun on your hip or chest is better than a bazooka in the truck. Opinions are like certain body parts. Everybody has one......This is mine.