I will just add from my experience as a kid playing around years ago, if you try to substitute payloads in a shotshell, you need to get it crimped properly again, otherwise the primer will blow the propellant out without igniting it, making a mess of unburned powder, wads, and the substituted projectile in your barrel.
I used to pull bullets out of .22 LR cases, replace the powder with 4f black (the smokeless would not ignite reliably without the tension of bullet), then press a rubber 6mm BB of the type used in toys in the case The edges of the case would cut a little ring of rubber off the BB, sizing it to .22 caliber. It was good for short range bird control in the barn, without shooting holes in the roof. This might be an option for the bears. Just be sure to clean your barrel well, as black powder fouling is corrosive.