So nearly everything we've been told about bear safety has been hinged on the notion that bear spray is a better defense weapon than a firearm. At least, that's the conclusions many reached. Turns out, it's not really a matter of better. It's a matter of the circumstance. Very good read. The big take-away for me is that there simply wasn't a large data pool on the use of bear spray with charging bears.

Of course, these studies largely dealt with brown bears and black bears are more relevant to the AT. On that note:

The 2010 study “Does Aversive Conditioning Reduce Human-Black Bear Conflict?” found that methods like chasing, rock throwing, or shooting black bears with nonlethal rubber shotgun slugs were as effective as, if not more effective than, pepper spray.

https://www.outsideonline.com/2401248/does-bear-spray-work