British De Lisle Commando Carbine with integrated suppressor

The WHI collections count several extremely rare historical firearms and the De Lisle carbine is one of them. Right from the start of the Second World War the British armed forces deploy a number of specialised commando units behind enemy lines. Consequently, they need weapons suitable for use during such covert missions. In 1943 Sir Malcolm Campbell of the Special Operations Executive therefore commissions a British Air Force engineer, William G. De Lisle, to design a prototype. This is developed at the Ford Motors factory in Dagenham.

The idea is to build the most silent weapon possible for use during missions in enemy territory/behind the lines and it is created by combining and adapting parts of three famous firearms. It is one of the “quietest” military firearms in history.

The weapon consists of the butt and bolt action of a Lee Enfield MK III rifle (modified to enable the use of the .45 ACP pistol cartridge), a magazine taken from the 1911 Colt pistol (capacity 7 cartridges) and the barrel of the Thompson machine gun fitted with a huge silencer. This silencer or suppressor is one of the item’s most distinctive features and accounts for more than half of the weapon’s total length.

Although prototypes of this weapon exist in a .22 calibre, the .45 ACP soon proves to be the most suitable calibre. The heavy projectile, in combination with a fairly reduced powder load, makes for an inherently subsonic calibre. The bullet can therefore never break through the sound barrier, and thus avoids the inevitable loud bang. The cartridge is nevertheless powerful enough to effectively eliminate enemies at short range (between 50 and 100 m).

However, the noise produced by the release of the gasses as the bullet leaves the barrel also needs to be taken into account. The answer comes in the shape of a large silencer of 5.1 cm in diameter. Combined with a very short barrel of a mere 17.5 cm, this  suppressor ensures that the gases released by the shot are already greatly reduced in force when they reach the front of the silencer. Several holes are also drilled in the end of the barrel to keep gas pressure as low as possible when the bullet is released.

As this silencer heats up after only a few shots, a wooden guard is placed underneath. The principle of the Lee Enfield bolt action is deliberately maintained. Experience with other silenced weapons deployed in similar missions, such as the Sten MKII(S), shows that the sound of the automatic loading principle is disturbing when only one shot is fired. Bolt action completely eliminates the noise after the shot, unless the shooter decides to reload manually. As operating in silence and secrecy is of the utmost importance, the steel underside of the bolt handle is even fitted with a piece of rubber, so as to muffle the striking of the handle against the butt-socket.

It is a weapon of legendary, almost mythical status, of which only some 130 were produced. This object is extra special because it is one of 17 or 18 test prototypes delivered by the Ford Dagenham Company in London. Six of these ended up in Belgium, and this specimen is one of those.

-Arthur Van Rossem, collection manager Portable Firearms, War Heritage Institute