De Lisle Commando carbine

JCFalkenbergIII · #1 (**permalink**) March 7th, 2008, 05:52 AM

Suppose that a small, specially trained unit will operate behind enemy lines. Their mission is very specific, they need to hit fast, disappear into the night and leave no residual evidence they were there. They must travel light and silently. They need a short, handy, quiet carbine length weapon. To insure that no residual evidence is left, empty brass can’t be scattered about. What weapon could fill such a bill? That was exactly the question the British pondered during 1942.
Where to find a ready-made, short, handy, silent, low recoil carbine for commando uses that wouldn’t scatter telltale brass? The answer was it didn’t exist at that time. The British realized they would have to build it themselves. It makes sense to use a cartridge already in the inventory. Additionally, it makes sense to use a readily available action and rework it. However the specifications would require more then a simple rework. Thus the De Lisle came to be.
In 1942 William De Lisle and Sir Malcolm Campbell began to develop a weapon that would meet the requirements of the Ordnance Board. By 1943 Prototypes were being prepared at the Sterling factory for submission to the board. It was decided to use the 45 ACP round as it was already in use by the British. They had quantities of Auto Ordnance Thompson’s and Colt 1911 pistols.
The De Lisle Commando carbine is basically a SMLE fitted with a M1911 magazine, a spent brass holder that catches the empties as they are extracted and ejected, a 8 .27 barrel and a 2 inch thick suppressor/silencer. A small forestock is under the suppressor. The weight was 8 lb, 2 oz. The rear sight was graduated for 50, 100, 150 and 200 yards. The front sight blade had tapered protecting ears.
Since the 45ACP is subsonic, the De Lisle is truly silent! The suppressor/silencer contains a series of baffles to muffle the sound of a round being fired. The action was reworked to feed and extract the 45 round as quietly as possible. Three factories were involved with building the De Lisle’s. Since each specimen is virtually a “One Off”, minor differences will be seen in original, individual guns.

Keystone Arms De Lisle Carbine (Photo courtesy of Keystone Arms)

SpecificationMeasurementCartridge:.45 ACP Length: 37.80in Weight:8lb 2ozBarrel Length:8.27inRifling:4 grooves LHMagazine:8 round removableProduction:1942-1945
130 De Lisle’s were built. They were extremely effective in terrorizing and harassing enemy troops. Often an enemy sentry would just drop in his tracks, dead. His fellow soldiers could not hear or see anything, yet a comrade was dead or wounded. A search conducted to find the shooter found nothing, not even expended brass. Soldiers who were constantly wondering if they were to be the next victim of a silent, unseen enemy became less effective fighters.
While the De Lisle didn’t account for large numbers of physical causalities the psychological effect on the enemy was well worth the effort.

The De Lisle had a shoulder stock, a barrel & sight radius 3 inches longer then a 1911 pistol; as a result it was very steady and quite accurate.

Collecting and Shooting the Military Surplus Rifle - Surplusrifle.com

JCFalkenbergIII · #2 (**permalink**) March 7th, 2008, 05:55 AM

The designer was William De Lisle. It was based on a Short, Magazine, Lee-Enfield Mk III* converted to .45 ACP by modifying the receiver, altering the bolt/bolthead, replacing the barrel with a modified Thompson submachine gun barrel, and using modified magazines from the M1911 pistol. The primary feature of the De Lisle was its very effective suppressor which made it very quiet in action - indeed working the bolt to chamber the next round makes a louder noise than firing a round.[1] The De Lisle carbine was used by British commandos and special forces, and was accurate to 250 metres.
The De Lisle was made in very limited numbers; 129 were produced during the period of 1942 to 1945 in three variations (Ford Dagenham Prototype, Sterling production and one Airborne prototype). Thompson submachine gun barrels were modified to provide the .45 calibre barrel, which was ported to provide a slow release of high pressure gas.
The suppressor, 2 inches in diameter, went all the way from the back of the barrel to well beyond the muzzle (the suppressor makes up half the overall length of the rifle), providing a very large volume of space to contain the gases produced by firing. This large volume was one of the keys to the effectiveness of the suppressor. The Lee-Enfield bolt was modified to feed the .45 ACP rounds, and the Lee-Enfield's magazine assembly was replaced with a new assembly that held a modified M1911 magazine. Because the cartridge was subsonic, the carbine was extremely quiet, possibly one of the quietest guns ever made.
The De Lisle was used by special military units during World War II and the Malayan Emergency

De Lisle carbine - Wikipedia, the free encyclopedia

Tony Williams · #3 (**permalink**) March 7th, 2008, 06:55 AM

It was a very interesting and technically successful weapon, but the relatively light weight of the .45 ACP bullet meant that its effective range was very limited: the trajectory curve was like a rainbow.

The modern approach is to load very long, heavy, low-drag bullets (see here: Untitled Document ). With the benefit of hindsight, something similar could have been done in WW2 by necking-out the .303 case straight to something in the .40-.45 region and loading it with a full-jacket big-game bullet (round-nosed, but still much heavier than the .45 ACP). Any specialist gun firm could have knocked that up quite quickly.