340 Weatherby Magnum: The 340 Weatherby Magnum was developed by necking up Weatherby’s already well established 300 Weatherby Magnum to a bullet diameter of .338 inches. This filled the Weatherby cartridge gap between their 300 Magnum and 375 Magnum. This cartridge went into mass production in 1963. The 340 Weatherby Magnum is very powerful, loaded […]