I was going to post this on an old thread that had reached four pages long, but it was locked. So... today I learned some particulars on one of the "Treadwell bears" that was shot by the Troopers. As you may recall, one of them was shot right in the head with a Brenneke slug as he was charging. However, the bear did not die from the slug to the head; it died from another one through the lungs. During the necropsy of the bear it was discovered that the famed Brenneke slug did not penetrate the brown bear's skull. These slugs have been around for a long time and are made of some pretty tough lead. Apparently not tough enough to penetrate a brown bear skull. I know of a lot of bears that have been killed with Brennekes, but this gives me pause about recommending a 12 gauge for bears.
P.S. Please, I beg of you, don't write that buckshot should be used for bears.