I've been doing wilderness trips for many years but have always used a shotgun and have had friends carry. Brown bears are the ones that attack mainly for defensive purposes. 90% of the time if a black bear attacks you its because it sees you as prey.
Black bear sows will tend to run their cubs up trees and then run off and come back when the threat has left since they are much better climbers compared to brown bears. During the year when their food starts to disappear and become scarce and when they become more active like during spring. This is most common in fall, winter (Black bears don't hibernate) early spring. Black bears however typically only attack hand when in a predatory mindset.
I actually have always carried a 12ga pump shotgun loaded with Winchester PDX1 Defenders and Brenneke Black Magic Magnum Bear Slugs and sometimes take some 00 Buckshot if I'm feeling brave.
