I know I will hear some crap for this but I did a little research and apparently the bear spray is more effective than trying to dispatch a bear while it is charging at you. From looking at the website and the reviews on it has saved more mauling than using a sidearm.
But I sure as heck would carry a revolver not a semi-auto and here is my reasoning. If you ever and a huge what IF get attacked by a bear and are able to grab your sidearm. Ever pressed a semi auto hard against something and tried firing it? The fact that the slide has to move back the cycle another round is another thing I don't like semi-auto for self defense with a bear. I would choose a light weight 44 mag and if I went the semi auto route if you did not have a 10mm and had a 45 I would buy a .460 Rowland conversion kit for it. If you did not feel like spending all that money or could not borrow a 44 mag.
http://www.fws.gov/mountain-prairie/...ar%20spray.pdf