Okay, I forgot to quote all of the appropriate posts I want to address and I am out of time, so I will simply say,
Bruce, I completely understand what happened to your buddy. He knew that the birdshot would not hurt the bear in any way and, I have seen this myself with black bear (never went into grizz country), would merely push it along. In this case, it didn't work, but at the time was probably considered solid common wisdom (at least I would have done it expecting the proper result).
Couple of guys posted immediate "go big or go home" stuff... really? Ever carry on long trails as a guide? Unless I was out hunting big stuff in big country, I wouldn't be carrying big medicine. I have normally gone in undergunned in almost any case I may have seen a grizzly (never seen one, but if i did I would have messed myself while trying to get away).
Those that said that he shouldn't have taken the shot because it wasn't humane, wrong, it didn't bother the bear, he just reacted differently than expected (yes a wild animal didn't react as expected, it happens).
Those who have said that back in the day when you basically shot everything were not far off. When men shot every bear they saw, ANY bear, bears stayed away. When Hunters shot every owl, raptor, etc that they saw, we had more rabbits and birds for hunting. Now that we have begun taking coyotes and wolves out here with a bounty, I think our deer, moose, elk, rabbit population will come up. I grew up with my father's freinds telling me to shoot all of these. Then the law changed and we couldnt do that anymore. Now there are no rabbits in NS.
Boomer (I think) you talked about common wisdom being shooting the animal with a load of buck shot in the face. I got taught the same thing as a kid and once I used my first pump shotgun, I found that pretty stupid. While I always was out hunting birds/rabbits, I carried one birdshot in the chamber, next round was always a slug (just in case), and the rest birdshot. My practice was to see how fast I could eject that birdshot round and fire the slug. I'll take the chance that a bear can still see me when I kill it than a blind, mad bear still coming at me. When actually hunting deer or black bear, the combination was slug, slug, birdshot, birdshot (since bird and rabbit season overlapped big game). I still managed my fair share of small game.
My thoughts,
Ted