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Country of origin

United Kingdom (designed in the U.S.)


Isaac Newton Lewis

Production began


Production ended

Mid 1930s

Weapon type

Light machine gun


.303 British
.30-06 Springfield
7.92×57mm Mauser


Gas-operated long stroke gas piston, rotating bolt

Overall length

965 mm / 38"

Barrel length

666 mm / 26.5"


12.7 kg / 28 lbs

Magazine/Cylinder capacity

47- to 97-round detachable pan magazine

Cyclic rate

500 to 600 RPM

Maximum effective range

up to 600 m / 650 yd practical
Official sights are marked up to 2100 yds

Muzzle velocity

745 m/s / 2445 ft/s

The Lewis gun, also known as the Lewis automatic machine gun or Lewis automatic rifle, is a U.S.-designed light machine gun perfected and mass-produced in the United Kingdom, and widely used by British troops during the First World War.

With its signature barrel cooling shroud and top-mounted pan magazine, the Lewis served to the end of the Korean War. It was also widely used as an aircraft machine gun, most often with the cooling shroud removed, during both World Wars.


Developed in 1911 by U.S. Army Colonel Isaac Newton Lewis, it was a reworking of a design by Samuel Maclean - the initial design proved to be too heavy with various gadgets, that it provided no combat value.

Isaac Lewis took the initial design, stripped all surrounding gadgets, and redesigned it in a quite straightforward manner. The end result is well-known to everyone.

The Lewis gun was mounted on an aeroplane, to demonstrate the viability of aircraft combat. However, US army had promptly rejected the whole idea, asserting that aeroplanes could not be viably used in warfare somehow else then in scouting role. About two years later, this illusion had been quite violently disrupted.

Later, around 1913, the Lewis had been tried by the Army for the role of infantry machine-gun, and again, was rejected, due to political differences between Isaac Lewis and General William Crozier. Frustrated with failed attempts to get the gun adopted, Lewis had retired from U.S. Army. He traveled to Europe shortly after, where in Belgium, he formed Armes Automatiques Lewis, which began the production of the Lewis gun in 1914. At the same time, Isaac Lewis had struck a deal with the Birmingham Small Arms Co., granting them license for Lewis gun production. Lewis received significant royalty payments from the production of the weapon, making him very rich.

Lewis guns were adapted in service in the U.K. and Belgium, and widely used in World War 1. The Germans, who suffered numerous casualties from this gun during air combat, nicknamed it the "Belgian Rattlesnake". Loaded with incendiary bullets, Lewis guns mounted on fast aeroplanes had proven to be lethal against hydrogen-filled German zeppelins. As a consequence, the Germans instantly adapted every captured Lewis gun that they had in service.

Reliable, cheap and simple, Lewis guns had served valiantly through the World War I, and were exported in various countries, including, ironically, the U.S. Among others, Tsarist Russia had procured a large number of Lewis guns, which served with the Red Army until the introduction of the Degtyaryov machine gun.

In a letter from T.E. Lawrence (A.K.A. Lawrence of Arabia) to his friend and biographer, the poet, Robert Graves, Lawrence noted that he carried an "air-Lewis gun" in the saddle bucket on his camel during the war.

During World War II, Lewis guns saw action again, mainly from 1941–1942. Employed by the U.K., they were used to compliment the lack of Bren light machine guns, and utilized stocks to the fullest possible extent.

Interestingly enough, the Mexican Mendoza RM-2 and German FG-42 seem to borrow heavily from the Lewis' design. In turn, the M60 machine gun borrows the action from FG-42 - and this is only one of a few examples of the Lewis' technical solutions living on through later generations of firearms.


Technically, Lewis guns are gas-operated, air-cooled weapons. The "stovepipe" barrel shroud is often mistaken for a water cooling jacket, but that is not so. Rather, Lewis guns have a tapering shroud project in front of the barrel. This form utilises the discharge of powder gases during fire to forcibly draw air through the shroud, thus cooling the barrel. Some sources indicate, however, that this shroud was quite unnecessary.

Pan magazines were of two capacities - one for 47 rounds and the other for 97 rounds. Large, 97-round drums were intended for the aircraft-installed guns, as they were quite sensitive to rough handling. Smaller-capacity 47-round drums were sturdier, but they were still quite sensitive to fouling, as their design had them open at the bottom.

Lewis guns had some interesting technical solutions - the pan was driven by a gas-operated cam, rather than a manually-wound spring. Another interesting feature was the return spring, which was similar to a clockwork spring, wound and unwound by another cam.

Lewis guns are considered to be among the best guns of World War I. Ideas incorporated in the weapon were used in numerous other firearms. Arguably, the Lewis gun is the ancestor of the whole class of light machine guns.