The Winchester Model 50 was an American 12 gauge semi-automatic shotgun designed by David Marshall Williams based on patents by Jonathan E. Browning in 1950 and produced by the Winchester Repeating Arms Company from 1954 to 1962. The Model 50 was a semi-automatic shotgun using a short recoil action. Unlike most other short recoil designs, the barrel on the Model 50 is completely static. Instead, the weapon uses a floating breech system consisting of a chamber and forcing cone patented by David Marshall Williams; when the weapon fires, this breech moves back about 0.1 inches (0.25 centimetres), causing the bolt to move backwards. A return spring pushes the bolt back forwards.