[mountainlion]

I had a bear try to break in one night. I think a 45 will only make a bear intruder mad. I am waiting on a 870 riot gun with a short barrel. I have a 45 Colt for two leg intruders.

[dblshot]

Get a big can or two of Bear Spray. Effective and a lot less messy to clean up.

[P8riot]

Depends on the bear. If it is a nominally sized black bear and the shot is well placed a 45Colt will do nicely. Now large (>350#) blacks, grizzlies, and browns are a different story.