The term W.W. II British Gun can be summarized as the Sten gun, a submachine gun used by the British military during World War II. The Sten gun was designed in 1940 and was mass-produced due to its low cost and ease of use. It was used by the British Army and Royal Navy throughout the war and was also supplied to resistance groups in occupied countries. The Sten gun was reliable and effective, and it remained in service until the late 1960s.