FWIW, when I was a kid back in the 1940's, food was scarce due to war rationing. All we had to eat was what we could grow on our farm and what we could harvest from the swamps and forests. Living near the huge Green Swamp of NC we bagged many a deer and black bear that ended up on the dining table. These critters were shot with buckshot. I'm sure there were slugs available but we had never heard of them.
Almost everyone in our isolated clearings old Stevens doubles or pumps of unknown genealogy. Many had only a single barrel. My family had an old Palmetto ( a pot metal wonder that still has a place of honor in our family)single barrel with a nail for a firing pin. Most of these old guns had their share of tape and wire holding the forend or stock in place. Paper shells were the norm as plastic didn't come out until the mid-1960's. Money was non-existent. Social security hadn't kicked in yet and welfare was considered beneath our dignity, so it was barter farm products for ammo. High powered rifles hadn't found their way to these isolated islands and clearings. If they had, we couldn't have afforded them anyway.
Everyone had a pack of hunting dogs. Deer and bear were plentiful. Buckshot was the only ammo available to us, so far as I know. I was a grown man when I first saw a pumpkin ball shotgun shell. It was just a large 12 gauge ball. I never knew anyone that used them but I shot one once and found it to be accurate enough.
Had it not been for buckshot, our meat supply would have been non-existent, except for the squirrels, coon, and other small game that could be harvested with small shot. My point is that buckshot is sufficient for bear. I have seen some very large black bears taken with buckshot. I never felt undergunned with 00 buck, as this was the only buckshot available in our part of the world.
I realize that there are better loads available now. We used what we had to use and it worked just fine. Believe me when I say that a bear being plagued by a pack of dogs is a mad critter and quite dangerous. 00 buck fed us during these times. My wife will not eat wild animals until this day due to the fact that she was raised on them and can't stand them now. She will cook them for me but she had a "belly full and a bait" of wild food to last her the rest of her life.
Since there are better loads available nowadays, no problem with me that you use them. Back during the Great Depression, those old paper shelled 2.75" 00 buckshot did a good job. They worked so well that I am sure that the new fangled 3" 000 buck won't bounce off them.