In 1940, a Desperate British Army Cobbled Together ‘Frankenstein’ Lewis Guns

WIB history November 28, 2016 0

A Mk.IV Lewis Gun with its mainspring running in a tube through the center of the skeleton stock. Royal Armouries photo Armorers rushed old...
A Mk.IV Lewis Gun with its mainspring running in a tube through the center of the skeleton stock. Royal Armouries photo

Armorers rushed old and damaged guns back into service


Following the disastrous Battle of France and the evacuation of the British Expeditionary Force from Dunkirk in early June 1940, the British Army desperately needed to rearm.

Part of London’s solution, in late 1940 and early 1941, was to develop a family of cheap and easy-to-manufacture “last-ditch” weapons.

These included the so-called “Mk.IV” version of the iconic Lewis Gun. The Frankenstein’s monster of machine guns.

At the time, there was a large number of damaged or incomplete Lewis Guns in British military stores, owing to shrinking stocks of spare parts and general wear and tear in service.

While it was possible to repair some of the guns, others required radical conversion. Typically, the Mk.IVs mixed parts from various guns and incorporated hastily-made replacement components.

One of the most problematic parts was the Lewis Gun’s coiled recoil spring, which was in increasingly short supply after Dunkirk. Armorers addressed this problem by the retrofitting Lewis Guns with the more readily-available main spring from the Bren light machine gun.

An unmodified and complete Mk.III aerial Lewis Gun. Source

Most of these guns were the Mk.III aircraft-mounted version, which lacked a stock and bipod. Armorers added a rudimentary metal skeleton butt stock. Some of the guns required new pistol grips and these too were made from simple strips of steel.

The Mk.III gun lacked a cooling shroud, so armorers attached a wooden foregrip to the gun’s gas tube. Simple triangular bipods were fitted, although some of the guns filled anti-aircraft roles and thus were mounted on anti-aircraft stands.

The British made similar modifications to other aerial Lewis Guns to adapt them for ground roles. Many complete Mk.III guns wound up with skeleton stocks and foregrips. The Brits similarly modified some 46,000 American .30-06 M1918 aircraft Lewis Guns that Britain had imported under Lend-Lease.

Historian Ian Skennerton describes the “Mk.IV” designation as an unofficial one, although it did appear in official correspondence. It’s unclear just how many Mk.IV Lewis Guns the British assembled and who exactly completed the work.

At least one example, pictured at top, survives in the Royal Armories’ collection.

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