Well, as my handle indicates, I'm an avid, if not rabid, fan of the K-frame. So, what I'm going to say next borders on blasphemy. I would probably pick a S&W N-frame .44 Magnum Mtn. Gun. Small enough to conceal under a coat, but serious enough for bear, God forbid. With reloading, which you would be doing cause if they ban guns they're certainly not going to allow the sale of ammo, you can develop .44 Special loads that are lighter than a .357 or loads that make your hand sting after one shot.
If I did choose a K-frame it'd be a 4" M66. Still powerful enough to take big game at close range, more concealable than the .44 Mtn Gun, and reloading consumes less lead and powder than the .44 Mag.
I'll throw in my long gun choices too. Shotgun: Rem 870. Rifle: Win 92 in 357 or 44 to match the handgun, or possibly the 94 in 30 WCF. Gas operated guns like the AR-15 get more picky about cleaning and reloaded ammo, and it's easier to totally destroy the action of the AR than the lever gun. The 30-30, even with it's "rainbow" trajectory has more penetration and stopping power than the .223, although ammo and components will be easier to find for the 223. Hmmmm, it's a tough choice, one I hope I never have to make for real. -Kframe