The .54 caliber is much cheaper to shoot, and still has a lot of energy for taking game. Many people believe them to be the perfect caliber for large game such as deer on up. I've never shot an elk with a muzzleloader, but would not be too worried about doing it with a .54 caliber as long as I could get in close and place my shot. Although let me say, I have a real soft spot for the .58 caliber. If you never shot one, they are really something to shoot...