Ask the realitives of the late victim ! Good lands man, if you got any gun, please shoot all you can before you mess with pepper spray, if you ar not wanting to be lunch. I Know you are serious about your question, and I am giving you the serious short version answer of mine.
Guns trump pepper spray on bears. If you are really worried about a bear attack, (and you should not be honestly), speaking from experience here. Then get a bigger gun, or load that puppy with heavy cast bullets, i assume your in the woods deer hunting, so you got the best of both worlds with the cast bullets that is, (using the caliber your talking about), and if you shoot your deer with a heavy cast, and hit him properly, he's on the table. If you need it against bear, you got very good penetration. With "what you got" that is my advice. Those wiser than I may be able to help you more.......