PA has a reputation for big bears. Plentiful food crops and genetics, I would guess. I have seen a couple big ones myself, though if you hang out at a bear check station like I did for a couple hunting seasons, most go about 200 lbs, or less. Seen quite a few that were smaller than my German Shepherd.
About 15 years ago, a buddy of mine shot one that weighed about 550 lbs. He had a full standing mount done, and the taxidermist did it in a two piece mount that kind of screwed together in the middle. I have seen Grizzly mounts that were smaller.
I once killed a small (about 175 lbs.) black bear in Maine with a .357 mag. One shot and down, but I admit a lot of luck, and would not use a .357 (125 SJHP no less) again on purpose. I was deer hunting at the time when the opportunity presented itself.
Larry