I've read and heard that buckshot is useless. Personal experience seems to indicate same.
1. Bangers
2. Spray
3. Slugs or some rifle .308 or bigger.
Who the hell runs into bears so often? I've seen many and most of the time wasn't armed. Even that moron took years hanging around grizzlies until he got eaten by one. If you're working in bear country I can see being careful, but the average walk in the woods seems hardly worth worrying about.
I'll bet there's a huge distortion in statistical probability here, but it seems to sell guns.
I choose an ATC for an M30 grenade launcher. You might only get one good shot anyhow, and it would be a heck of a lot of fun the other 99.998% of the time.