I would want some poundage, at least 55#-60# or more for a bear with a selfbow, and some heavy arrows-at least 600 grains or more, preferably. Like Mike said, they have thick hair plus a thick layer of fat. We were skinning a big old one once and a good handfull of .22 bullets and shotgun pellets fell out when we pulled the hide off, they had just penetrated the skin and got stuck in the fat layer. They don't die real easy with a .30/30-I've seen some shot bears come down a tree and take a few dogs with'em.