I grew up in northern Saskatchewan and wound up going in the bush after my fair share of bears that had been wounded by others. If you are hunting bears I would recommend at least a .308. Defence is something different. This would indicate that you are being charged/attacked. When I used to go in after wounded bears I carried a Mossberg 500 with an 18" barrel. Nice and handy in the bush. I used to load slug, slug, slug, 00 buck, 00 buck. As I told a friend of mine, if they come at you in the willows, the first 2 rounds you just point and shoot. If he's still coming, by that time you don't have to aim. There have been a couple times when I've emptied all 5, and I'm still around. A rifle is great, but it is precise, and when you get charged the adrenilan is off the charts. You want instant stopping power, and the bigger the chunk of lead the better, as far as I'm concerned.