Well, I was going to pass on this but what the hell..Okay, you want a good warm load; something about like 30 grains of Triple Seven 3fff. Get close to him (her) and stick it close to their face. (give's you the advantage of smoke, noise, heat, and concussion) You MIGHT have 1/3rd of a chance but even that would be stretching the odds; all depending on the type and size of the bear. When I got through using 6 shots out of a Walker on a bear one time the bear was stone dead. One ear all burned and shriveled up, the other ear burned so bad it was dry and crumbly and shot half off, both eyes burned out, nose burned real bad, all the facial hair burned off, jawbone broken in 2 places and about half of his teeth were knocked out..I wasn't looking for it either and had no idea it was anywhere around or my Marlin lever action 4 shot .45-70 (with rounds hand loaded to the equivelent of .45-140) would have been in my hand. All I was trying to do was take a peaceful piss....'58? It might can be done but it wouldn't be fun....