I have taken a boatload of game with both the .454 and the .475 and the .475 is simply a bigger hammer. Velocity doesn't make up for the larger diameter or heavier bullet capability (and I have used 400 grain bullets in the Casull) of the .475 or .480. While none of this may make a lick of difference on whitetail where you can get away with even those really light bullets, move up to larger and thicker skinned game and I will take the advantage of the bigger caliber.