.338-378 Weatherby Magnum

The .338-378 Weatherby Magnum is based on the .338-378 KT, a wildcat cartridge created by Elmer Keith and R.W. "Bob" Thomson in 1966. The KT is based on the .378 Weatherby Magnum cartridge but is shorter by 1/4" and necked down to a .338 caliber bullet.