Of course there are various handguns and handgun rounds that are theoretically capable, and some proven, if anomalously, to be capable of killing bears and other large animals, but none are any adequate substitute for a suitable rifle. I am comforted by the .44 Mag 629 on my hip, when luring lions and bears with a predator call, but my first line of aggression and "defense", if it may so be called, is my Winchester M70 Featherweight .30-06. Shooting bears with a handgun, on purpose, is a marginally ethical stunt, except, I suppose, if you are merely assassinating a baited bear from the safety of a tree stand, or dispatching a bayed or treed animal on its last legs, at its last resort. But generally speaking, handguns are not up to the task of sport hunting for bears, and should be relegated to defensive use, when circumstances have deteriorated, by your inattention, to the point where gnawing is involved...