I'd agree with those that recommend
bear spray versus a handgun for bear defense. That said, if you really want a handgun for defense, against bears, then you will need the biggest caliber you can handle and shoot effectively for any chance of success. And DA is what you want for any chance of a follow up shot.
A .44 Magnum would be a minimum in my opinion and with full house loads as well. While I've carried, and still own several Ruger single actions in .44 Magnum, and three Smith Model 29's (one is actually a 629), I recently bought and have been carrying a Smith Model 69 here on our farm in KY.
The Model 69 is a 5-shot "L" frame Smith, weighs 37.5 oz's. empty, and is chambered for the .44 Magnum. The weight should indicate severe (some would opine "heroic" recoil), but in point of fact, it's not all that bad. The gun does come back fast in the hand on firing, but Smith's factory rubber grips tame all that. Too, the front part of the grip extends low on the rear of the trigger guard, eliminating that 2nd finger crunch. It's downright comfortable to shoot, and those grips are the only ones I've ever come across that handle truly heavy recoil effectively.
Accuracy in this new revolver, is superb...well below 2" with my handloads at full velocity, and nearly as good with factory fodder. Too, it's stainless construction makes it ideal for back country use where the lack of a daily cleaning regimen will make short, rusty work of a blued steel gun.
The 69 is innovative on several points: SS construction, sleeved barrel, light weight, "L" frame for comfort in medium sized hands...among others. And yes, it does have that cursed internal lock...tho in all honesty, it's not been a problem whatsoever on several of my more current Smiths.
Compared to the "N" frame Smith's, the 69 is lighter, fits my hands better than the "N" frame, but does so by giving up that 6th shot.
Here's the weight comparison, S&W M69 vs. M629, obviously both in .44 Magnum as shown on my wife's postal scale.
M69: Empty: 37.5 oz. Loaded: 41.6 oz.
M629: Empty: 45.5 oz. Loaded: 50.4 oz.
Here's a pic of my 629 (5" bbl.) with the Model 69 & its 4.25" bbl. below it. Note the grip differences. BTW, that 629 has a similar rubber grip as bought, but I find it not as comfortable in the hand as the M69. YMMV. The 2nd shows what the "L" frame 69 is capable of with good loads...a mild one in this case, (~1100 fps).
HTH's Rod