A 6" S&W M629 stainless or M29 blued would work fine.
My 6" M29-5 is stoked with the hard-thumpin' Federal "Castcore" 300gn. hard cast, flat nose bullet that will blow a big hole through just about anything and I've taken scores of deer with this particular combo through the years.
It is topped with a Bushnell 1st generation "Holosight" red dot sight that has incredible speed (I've TWICE dropped three deer in the wild in scant seconds while hunting and taken several deer with heart shots that were running broadside . . . the furthest at 65 yds. in a clear cut. Umm . . . yes . . . it would do the same to a big bear that was charging you, just swing, put the dot on the spot and touch off a round.
My holster is a humble Uncle Mikes made for a 6" large frame revolver and I've cut the front top strap area come to accomodate the Holosight. As you can see by the photo, the security is provided over the Holosight with the original snap strap . . . and I've NEVER, ever had a problem with the gun staying in the holster, including going up and down countless trees and using climbers.
It also is comfortable to carry on the hip for long days in the woods!
Here's the wheelgun on a Piebald whitetail hyde that I harvested a couple of years ago with this rig, along with the mighty 300gn. Federal Castcore. That round would thump a bear real, real good! Grips are in Hogue's "Camolamo."
T.