I think I read that the success rate on black bears for bear spray was somewhere in the 80s% range. The info I read said it was less effective on blacks than on brown bears.

Even so, and even considering rabies, spray is probably the best first choice. But given that nothing's perfect, I think it's a very idea to carry a gun where bears may become an issue.

The thing with bears is, you want them to stop right away. Bear spray gets that result a lot better than a gun does in most cases. The gun should logically be the back up to the bear spray.

Now, the guy on this show is alone. If he's following the logic of bear spray first, gun second, then the shotgun is pretty useless. If the spray fails, will he be able to bring a long gun into play? (I almost said "to bear" there, but that would have been an unbearable pun.) If the bear continues to attack, I'd say it's likely he'd find himself on the ground. A revolver would be better in that situation. A second person with a gun would be preferable. I'm pretty sure that he and the producers were banking on him not crossing paths with an angry/sick/crazy bear. Or else he had someone just off camera, on the ground, as a safety.