Colonel Isaac Newton Lewis, a U.S. Army officer, developed the light machine gun named after him in the years prior to World War I. Lewis attempted to get his design for a machine gun adopted by the U.S. Army, but failed. General William Crozier, then Chief of Ordnance, usually receives most of the blame for the Army’s rejection of the Lewis Gun. The issue became controversial because of the lack of machine guns in the U.S. Army when it went to France beginning in 1917. By that time the Lewis Gun had a proven track record as a successful combat arm. The gun’s success made the Army’s, and Crozier’s rejection of a design from one of their own officers look rather poor.
Lewis Gun complete with spare magazine and pouch. 
The markings on our BSA built example, along with a tag added by Winchester when this gun became part of their factory collection
A bottom view of a magazine and the two-magazine pouch for a Lewis Gun. 
Closer view of the side of the receiver and the distinctive fins that keep the gun from overheating. 
Full profile view of one of our two Lewis Guns
Back to 1913, Lewis had retired from the Army and move to Belgium to set-up production for the Lewis Gun in Liege. The Belgian Army purchased a small number of Lewis Guns that year. Lewis also sold the production rights of the Lewis Gun to Birmingham Small Arms in England. BSA began producing Lewis Guns under license for the British Army.
The first combat use of the Lewis Gun occurred with the Belgian Army in the summer of 1914, which earned it the nickname “Belgian Rattlesnake” from the German soldiers who faced it. The Lewis gun help change machine gun tactics during the First World War. The gun weighed 28 pounds, compared to almost 100 pounds for a British Vickers Gun with its tripod and water filled jacket, and the Vickers was one of the lighter water-cooled guns at the time. A single soldier could carry and operate the Lewis Gun, and by 1916 BSA had built enough Lewis Guns so that every rifle platoon in the British Army had one.
By the end of the war, BSA built nearly 150,000 Lewis Guns, and they outnumbered Vickers Guns by roughly 2 to 1. Chambered in .303 and capable of 500 rounds per minute the Lewis gun proved itself in World War I, and went on to fight through World War II. Ultimately, even though Germans made use of captured Lewis Guns, the American military did not use them during World War I. The Marine Corps had adopted the gun in .30-06, but were re-issued the French CSRG, more commonly known as the Chauchat. The French machine gun and the decision to replace the Lewis Gun was widely disliked by the Marines.
The Lewis Gun has both distinctive looks, and proven combat record. The unique barrel jacket hides the fins that effectively air-cool the gun by acting as a heat sink and helping to draw air through the jacket when the gun is fired. Its performance is arguably the best of any light machine gun of World War I and provided vital firepower for the Allies.
