I've been tempted to buy a shotgun for survival for a long time. The shotgun seems to be the most versatile. Easy to get shells, you can hunt anything with it, best for self defense...but then I remember the statistics. Lots of people shoot bears and the bear still kills them (a grizzly can still function for a time after it's heart has stopped pumping). I don't know of a single case where properly used pepper spray wasn't 100% effective.

Still tempted to buy the shotgun but I haven't found an argument strong enough to get it yet.