Brought to market by Roy Weatherby in 1945 the 300 WBY was said to be 50 years ahead of its time. The 300 WBY is an ultra versatile 30 caliber option that is great for a variety of hunting situations. – CARTRIDGE SPECS – Bullet Diameter: .308 (7.8mm) – Common Reference: .30 Caliber – Max Case Length: 2.825 – 170 Grain Hammer Custom