Mike, my brother definitely knows the power behind bears. Back in the 70's he was bird hunting with my other brother and a brother-in-law. The brother-in-law had a side by side shotgun. He doesn't know why, but he put buck shot in his second barrel, and used bird in his other. My brother-in-law also had with him his 5 year old son. they were walking through some very tall ferns (4' tall). My brother-in-law walked in the middle, while my two other brothers flanked him by 50 yards either side. A black bear suddenly stood up right in front of my brother-in-law not more than 20 feet away! She was mad, snapping her teeth and growling. He doesn't even remember thinking what to do, he just brought his shot gun up and fired both barrels. The bear rolled backwards, and never got up. That's when the excitement really started. What was unbeknown to them was the bear was a mamma. She had 2, year old cubs with her; and they went crazy. One ran right at my brother (the one who lives in VA now) and the third shotgun blast brought it down. The other bear ran towards my other brother, he had a single barrel 20 ga shot gun. He fired at the bear hitting it in the face but it kept coming. In shear panic, my brother couldn't load another shell and started to scream. My brother ran over and put two more shots into the bear to bring it down. From what they guessed, the whole account took about two minutes to go down. The year old bears weighted just over 100 pounds. The mother was a big one, she weighted 300 lbs.
By the way, they came back to camp without any birds.