Lewis Gun
First World War–era light machine gun. Designed privately in the United States though not adopted there, the design was finalised and mass-produced in the United Kingdom, and widely used by troops of the British Empire during the war.
The Lewis was produced by BSA and Savage Arms during WW1, and although the two versions were largely similar, enough differences existed to stop them being completely interchangeable, although this was rectified by the time of the Second World War.