tjf76 - is the Glock 23 a 40 S&W or a 10mm? Just a question there because I'm not familiar with the Glock designations. The emphasis on the 357 over the 40 S&W was generic to the calibers, not the shooter.
OK, you have 14-15 rounds of Glock 23 stuff vs the 5 rounds in the revolver which certainly gives you a firepower advantage, especially if you can handle that 23 in a close quarters situation with a fast moving predator. Howsoever, I'm not aware of a Black Bear attack on a human in NYS - most often they shy away from us and would not attack us if we were fishing their favorite Salmon stream the way a Grizzly or Brown Bear would but, sometimes they get whizzed off at us and that may call for a, umm, defensive shooting situation. If it is up close and personal and you have your 23 loaded for Bear, so to speak, you should be able to extricate yourself from the situation without harm to you (increased heartbeat rates are OK in that situation) and possibly a new rug.
If you are going to stick with your G23, I would recommend heavy soft nosed or hard cast square shouldered bullets that could penetrate and break bone. 180 - 200 gns is a good weight range for that 400 bore. You may wish to (as in 'should') avoid hollow-points in favor of penetration. Also, I would practice for the possibilities - Bear do not stand on their hind feet and talk at ya before they decide to chew your azz (LOL), except in Hollywood - they come in low and fast like a dog or a hog, bowl you right over and rip you apart. I don't know too many guys who can stand up to a low fast charge by a bruin weighing 3-400 lbs, which is why I suggested the 357 with heavier loads for its penetration.
OK, I've flapped off enough but I do wish you good luck and hope you don't ever find yourself in a position to prove the point. Mikey.