As some have already indicated, the biggest myth of "bear protection" is the thought that if it is a really big bullet, you are safer. Shot placement will be absolutely essential to stopping a bear encounter, and if the placement is proper, most cartridges suitable for deer will do the job. If you don't hit the central nervous system, nothing you can shoot from your shoulder will do much to save you. The other idea with which I agree is that worrying about having enough gun to stop a bear is often a concern of those who don't spend a lot of time in bear country. Use a gun suitable for what you are hunting, pay attention to your surroundings to avoid surprises, and stop letting irrational fear ruin your experience of some of the most beautiful environments on the planet.