The Lewis gun’s story begins in the United States in 1911, when Colonel Isaac Newton Lewis developed the weapon based on work by Samuel Maclean. Despite its promise, the U.S. Army rejected the design, likely due to Lewis’s conflict with General William Crozier of the Ordnance Department. Frustrated, Lewis left the army and eventually the country, establishing a company in Liège, Belgium, in 1913. There, he partnered with the Birmingham Small Arms Company (BSA) in Britain to refine the weapon. The Belgian Army bought a small number of guns, but with the outbreak of the First World War and the threat of invasion, Lewis moved production to England. With the war’s demands, BSA began producing the weapon in 1914 under the name Model 1914, and the British officially adopted it in October 1915 as the “Gun, Lewis, .303-cal.” Manufacturing was split between BSA in the United Kingdom and Savage Arms in the United States. While the British-made versions were chambered for .303 British ammunition, Savage produced models in both .30-06 and .303. These variations created some early interchangeability issues, though by the Second World War most of these differences had been resolved. The gun quickly became a staple of British and Commonwealth forces, used not only on the ground but also mounted on aircraft. The Lewis gun was distinctive for its barrel shroud and internal aluminum heat sink, designed to cool the weapon during sustained fire. Air drawn over the barrel by muzzle blast improved cooling, though wartime experience later showed that the weapon worked effectively even without the shroud, particularly in aircraft use where airflow provided natural cooling. The gun’s top-mounted pan magazine, holding either 47 or 97 rounds, gave it a unique silhouette. Driven mechanically rather than by springs, the magazine reliably fed rounds into the action. Another innovation was the use of a spiral spring, similar to a clock spring, housed in front of the trigger, which powered the recoil system. Weighing just 28 pounds, about half the weight of a Vickers heavy machine gun, the Lewis was considered light enough for one soldier to carry and operate. Its rate of fire averaged 500 to 600 rounds per minute, though an aircraft variant fitted with a recoil enhancer could reach 800 rounds per minute. Its portability made it popular with infantry, while its relatively simple design and reliability led to widespread use in both World Wars. The Japanese even copied the design and used it extensively during the Second World War. The gun’s impact extended beyond the First World War. During the interwar years, many Lewis guns remained in service, and in the Second World War they were again issued, particularly to the British Home Guard and in anti-aircraft roles. The Royal Navy retained the full cooling system for deck-mounted versions, while older aircraft guns were stripped of their shrouds. The gun continued in limited use during the Korean War, marking a service life that stretched across four decades and two world wars. By then, newer weapons had surpassed it, but the Lewis gun had left its mark as one of the most important light machine guns of the twentieth century.