The set contains No. 4 M12 trench guns. two with smooth barrels and two with drilled barrels. They were used in World War I until Vietnam. The version with a smooth barrel is also used by American police. Winchester M1912 The Wichester M1912 was the natural evolution of the Winchester M1897. The rifle was equipped in the front section with a bayonet mount, a key component in close combat in trenches. 12, 16,18,20 or 28 Gauge buckshot cartridges could be used. The weapon was employed against Pancho Villa's Mexicans in 1916, in World War I, by the various U.S. police forces in the 1930s, especially on the Pacific front in World War II, in the Korean War, and in Vietnam