You can never have to much fire power Im not familiar with the 10mm. Personally I prefer revolvers for their reliability. The 500 S&W, 460 S&W, or 454 Casull would be my top choices for big bears in Alaska. I really like the 460 S&W because it will also shoot 454 Casull and 45 long Colt ammo. The only drawback to the S&W's is the pistols chambered for them are fairly big and heavy but being heavier they do manage the recoil pretty well. You can get the Casull in much smaller and lighter pistols but Im not sure how the recoil would be.