I'm a big fan of the .257 roy, and wouldn't hesitate to use it on deer but I wouldn't use it for bear. Maybe i'm under-estimating my shooting ability but bears are really tough critters. On the other hand I've seen guys bear hunting with lever action 30-30's and 44 mag's. Both I'm sure have killed plenty of bears but I'm a fan of using WAY too much gun to dispatch animals........just me though.