What kind of bears are we talking about here?
Blacks or Griz/Brown?
Cutting the gun down? Ok not a bad idea. Definetly iron sites. The bigger the bullet the better. Go with the 220s.
Trade it in on a handgun? Not unless you use the gun alot and are good with it. Handguns are much harde to master and not for the novis user if life and limb are depending upon it.
I would say trade it in on a 12 guage shotgun (pump or auto) with a short barrel. A good gun with lots of stopping power at short range.