Weapons of the British Army

Lewis Light Machine Gun

The Lewis gun was invented by US Army Colonel Isaac Newton Lewis in 1911.  It was not adopted by the US Army, so Lewis travelled to Belgium in 1913 where  he set up  the Armes Automatique Lewis company in Liège to facilitate commercial production of the gun.

Lewis had been working closely with British arms manufacturer The Birmingham Small Arms Company Limited (BSA) in an effort to overcome some of the production difficulties of the weapon.  The Belgians bought a small number of Lewises in 1913, using the .303 British round, and in 1914, BSA purchased a licence to manufacture the Lewis machine gun in England.

Lewis and his factory moved to England before 1914, away from possible seizure in the event of a German invasion. The Belgian Army acquired only a handful of his guns, probably only just in double figures. They were not on general issue in the Belgian Army. They were used only in a few forays by motor vehicles, south of Antwerp, against the flank of the invading German Army.

My Lewis gun, used in re-enactment and living history displays, is a gas-powered replica.

It was built by WTAC, and uses butane and oxygen gases to produce a realistic firing effect.

The onset of World War I increased demand for the Lewis gun, and BSA began production (under the designation Model 1914). The design was officially approved for service on 15 October 1915 under the designation "Gun, Lewis, .303-cal."

No Lewis guns were produced in Belgium during World War I


The Lewis gun was gas operated. A portion of the expanding propellant gas was tapped off from the barrel, driving a piston to the rear against a spring. The piston was fitted with a vertical post at its rear which rode in a helical cam track in the bolt, rotating it at the end of its travel nearest the breech. This allowed the three locking lugs at the rear of the bolt to engage in recesses in the gun's body to lock it into place. The post also carried a fixed firing pin, which protruded through an aperture in the front of the bolt, firing the next round at the foremost part of the piston's travel.

The gun was designed with an aluminium barrel-shroud which caused the muzzle blast to draw air over the barrel and cool it. 

The gun's cyclic rate of fire was approximately 500–600 rounds per minute. It weighed 28 lb (12.7 kg), only about half as much as a typical medium machine gun of the era, such as the Vickers machine gun and was chosen in part because, being more portable than a heavy machine gun, it could be carried and used by one soldier. BSA even produced at least one model (the "B.S.A. Light Infantry Pattern Lewis Gun", which lacked the aluminium barrel shroud and had a wooden fore grip) designed as a form of assault weapon.  The circular magazine contained 47 rounds, with a 97 round magazine used in aircraft.


The Lewis gun has the distinction of being the first machine gun fired from an aeroplane; on 7 June 1912 Captain Charles Chandler of the US Army fired a prototype Lewis gun from the foot-bar of a Wright Model B Flyer.  When mounted in aircraft the cooling shroud was removed as the gun was cooled by the aircraft motion.

Nicknamed 'The Belgian Rattlesnake' by German forces who came up against the weapon in 1914, the Lewis was formally adopted as the standard issue British Army machine gun from the close of 1915.  By 1916 approximately 50,000 had been produced.  Although in 1915 each British battalion on the Western Front had just four Lewis Guns, by 1917 each infantry section boasted its own Lewis gunner and backup, with battalions by now deploying 46 Lewis Guns.

As a light automatic machine gun it was considered the best and most reliable available at the time and was soon adapted for use both at sea by the Royal Navy, and for use in the air by aircraft observers (with the Vickers Gun used for forward firing through the aircraft's propeller blades).  When used in the air the Lewis' air cooling jacket and fins could be dispensed with: it then weighed just 9kg.

The Lewis Gun weighed 28lbs (13kg), making it possible for one man to carry and operate.  It was 50.5 inches (1.28m) long, and the barrel was 26.5 inches (67cm) long.  It had a muzzle velocity of 2440 feet per second (740 m/s), and an effective firing range of 880 yards (800m), although the maximum firing range was 3500 yards (2 miles or 3.2km)