Man, I would NEVER go after a grizzly with a .308 or 7mm-08 or anything in that size. I've read story's where guides have emptied a .300 Win Mag into them and they didn't stop. I've had whitetail doe take three .308 150 gr. in the lungs and not drop. Kind of like the movie "Blazing Saddles" where the sheriff is putting on his gun to go help the townspeople with "Mongo" and his buddy says "don't shoot him, you'll only make him mad"!