I'd personally recommend the Ruger Super Redhawk in .454 Casull. It's a very reliable and accurate handgun, comes with machined in integral scope mounts and rings, has plenty of power for hunting any type of big game, but is flexible in that it also can shoot the much lighter .45 Colt. And if you handload you can load up .45 Colt using data for Ruger/Thompson Center only loads and duplicate .44 Mag performance which is midway between the rather lethargic standard pressure .45 Colt and the full power .454 Casull.

Mike