I have to go along with NoMercy448 on this (where legal of course). The only thing that runs through my mind where big bear hunting is involved is why would you consider using a handgun when you should have a rifle of adequate stopping power in the first place. And as far as using a handgun for bear as a defensive weapon in, as you put it, tight quarters I would suggest the largest caliber you can handle. A bear coming down on you will likely only allow you to get one shot off anyway. Maybe two if the first one hits hard enough. The 500 S&W would be my choice.
Just watching bear charges on TV gives me the willies. I had a 300+ lb black bear come at me after I jumped it and gut shot it with the first round. But really don't think he was coming for me, he just didn't know where the first shot came from. The second and third made that point clear to him but too late. (I was using a Rem 760 which is why I was able to get the shots off so fast.)