Polar bear attacks occur most often at sites of human habitation, such as hunting camps, weather stations, and towns. Compared to other bears, polar bears are more willing to consider humans as prey. Consequently, the person attacked is usually killed unless the polar bear is killed first.
http://www.seaworld.org/infobooks/Po...bbehavior.html

According to the Alaska Science Center, a 12 gauge shotgun with slugs has been the most effective weapon. There have been fewer injuries as a result of only carrying lethal loads in the shotgun, as opposed to deterrent rounds.
http://en.wikipedia.org/wiki/Brown_Bear

HUMAN BEING Defense Council
Remington Arms Company, Inc.
870 Remington Drive
P.O. Box 700
Madison, NC 27025-0700
http://www.remington.com/