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De Lisle Silent Carbine
-~- Written and Researched by Stefan Bridle -~-
De Lisle Silent Carbine
When the Second World War started there were very few silent firearms in the world. In 1942 William De Lisle and Sir Malcolm Campbell (of combined operations HQ) began work on a totally silent rifle for use on covert operations. Three silenced rifles were proposed to the Ordnance Board in 1943 by De Lisle, two in .22 RF calibre and one in .45 ACP. The .22 rifles were an auto-loader and a machine carbine, which featured a waxed paper belt, but neither of these designs filled any requirement so they were not proceeded with. The De Lisle carbine that was accepted made use of the American .45 Automatic Colt Pistol (ACP) round because it travelled at subsonic velocities and therefore did not make a distinctive crack as it reached the speed of sound. This particular round was chosen because it was already in British service for the Thompson sub machine gun and the Colt Model 1911 pistol, the magazine for which could be modified and used in the De Lisle rifle. Despite the fact that the .45 ACP round was only a pistol cartridge the De Lisle had a barrel length of 8.27 inches, compared with the 5 inches of the Colt 1911. This noticeably increased range and accuracy.
Prototypes of the De Lisle were made at the Sterling factory in Dagenham, East London for testing by the ordnance board in 1943-1944. They were tested against the silenced Sten Mk.2 and fared very well in the endurance and sound level tests. It is recorded that after successful trials on the Campbell estate, the carbine was offered to the Senior Officer to shoot and he shot at some ducks feeding on the other side of the lake, purportedly some 400 yards distant. One duck was shot dead through the neck and upon recovery of the "target" the officer coolly remarked, "I'm rather out of practice, so perhaps it's hardly fair to blame the gun. Actually I aimed for its head." Production was begun at the Stirling factory as an order for 500 carbines was placed. There were two planned models, one with a folding metal stock and one using the standard SMLE stock (weighing 7 Lb. 2.5oz and 8Lb 4oz respectively). None of the airborne model with the folding stock were produced and only 130 of the standard model were built.
Used or condemned SMLE rifles were used as the basis for the De Lisle. The receiver had the charger guide removed and an ejector set into the left of the body. The magazine housing was modified to take Colt 1911 magazines and it was re-chambered for .45 ACP ammunition. The bolt was shortened to 3.6inches and the bolt head recessed and extractor modified. A Bakelite insert was fitted into the cocking handle using a dovetail joint to reduce the noise made when closing the bolt. Beyond the muzzle of the barrel was an expansion chamber and a series of 13 baffles inside a 2-inch diameter tube. The baffles were positioned on 2 locating rods to align the bullet passage holes. The baffles were cut and arranged to form an ‘archamedies screw’ effect.
The De Lisle had a conventional leaf back sight graduated at 50, 100, 150 and 200 yards, the base of which was riveted to the silencer casing. The blade foresight had 2 protecting wars. The woodwork of the SMLE was cut off level with the receiver and an 8-inch long fore wood was attached beneath the silencer. The butt trap contained a piece cleaning rod, which measures 15 inches when fitted together. The De Lisle is still the world’s only truly silent rifle and though it experienced limited success in Europe is was very effective in the jungles of the Middle East.
