Well I worked at a Sporting goods store where they registered and weighed black bears. I talk to people who hunt them with dogs and shoot them out of a tree. I have seen bears that are 400 lbs or even more. I have only shot one over bait and a 225 gr Nosler Partition through the heart stopped him in his tracks. I think hunting with dogs is the way to go but it is not legal in Minnesota.
Wisconsin allows it and it is popular.
I think people who use iron sights at dusk in the woods probably think bears are hard to kill because it is hard to make a clean shot.
If you have a good scope that might make all the difference.

I like to do my hunting BEFORE I pull the trigger!
There is only one kind of dead, but there are many different kinds of wounded.