BEAR MACE, or get eaten, your choice. A charging bear moves at 35+ mph. Even if he starts 50 yards away that gives you seconds to react to a bear bounding towards you, and then clean the Sh** out of your pants, draw, aim(which is going to be hard to do at a bounding bear while shaking), and make several effective hits which will be necessary for the bear to even know your shooting. You'd be better off shooting in the air hoping the noise scares him. And if you were equipped with a can of bear mace, simply grab the can attached to your hip, turn to face bear, and hold the trigger. Now you have a scared bear that can't see or breath as opposed to a really pissed off bear that is dead set on making you a bear turd. Scared bears run, pissed off injured bears make a last stand effort to defend their lives and will gore you until they die.
Hunting is far different than any other activity where you would encounter a bear. You will most likely hunt from a stand over bait, and see the bear before it see's you. Hiking or during another such activity, the bear will see you long before you see it and decide whether to retreat or stand it's ground. If it decides to stand it's ground, it will be on you in seconds, leaving you so little time to prepare to fight that you will most likely panic and never even get a shot off.
Do as you please, but I have discussed this with numerous outdoor experts, and all have given the same advice, wear a bear bell and carry a can of bear mace.
Or buy a .500 mag and get some of EC's sub-nuclear reloads, as the muzzle flash and concussion will likely kill the bear all on it's own, or at least blind it and deafen long enough for you to actually do something other than get eaten.