The 460 is better suited to longer range shots due to its flatter trajectory. The cartridge was built around the XVR's gain twist rifling and longer barrels, so I'm not sure how this applies to a 2.75" bbl version. For brown bear, you want the biggest, heaviest, bullet as fast as you can push it...and you won't be taking long range shots for bear defense.

The shorter barrels will also help start signal fires around you in a survival scenario. Also, if you don't hit the bear (or set it on fire), bears fear fire more than humans. :P

You need one of these, don't you?
Model 500ES - Emergency Survival Tool Kit
Model 500ES - Emergency Survival Tool Kit contains:
-Smith & Wesson Model 500, 2 3/4" Barrel with Bright Orange Hogue® recoil reducing grip
-Waterproof Storm® Case
-Blast Match™ Firestarter and WetFire tender
-Saber Cut™ Saw with fabric sheath
-Jet Scream™ whistle
-Star Flash™ signal mirror
-Polaris® compass
-Two MPI Mylar Space® Emergency Blankets
-Smith & Wesson Extreme Ops Liner Lock Folding Knife with Black Sheath
-"Bear Attacks of the Century - True Stories of Courage and Survival" book by Larry Mueller and Marguerite Reiss
Exercise your right to: Bear Arms