Id shoot first with the ML in the upper chest or neck. Either that or in the head. Only 2 shots will stop that bear in its tracks. You either sever the spinal cord at the neck or take out the brain. Either one is going to take a weapon that has some energy. For a handgun, imo, 40 cal is the least Id go with.
Some will tell you a 9mm is enough, some will say a 7th grader with a baseball, it's all what makes you feel better. If I had only a 9mm id definatly not shoot for a between the eyes shot. You might kill the hummingbird or spotted owl in the tree form your richochet off his super thick, high angled skull. Lol
Now that the regs are changed, Id carry a 40 cal minimum. And like Bone said, its the first shot that counts. Id wait till its about 10 to 20 feet away. And then unleash my hard cast .357 into his skull. The next 4 would go DA mode center mass. If I needed more, Id cry. Lol