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The de Lisle Carbine: The Most Awesome Gun You’ve Never Heard
By: +Chris Baker 

Back in WWII, there were limited options for soldiers on covert operations who needed firearms with some stealth. Suppressors had been around for 40 years and were effective at reducing a weapons’ report to “hearing safe” levels, but not “sneak around an enemy encampment” kind of quiet. William Godfray de Lisle, a British civilian working for the Air Ministry, came up with a solution. Using the ubiquitous English Lee-Enfield SMLE MkIII bolt action rifle and the barrel from an American Thompson submachine gun, he created an integrally suppressed carbine that fired the .45 ACP cartridge from a modified M1911 pistol magazine. In other words, de Lisle added a suppressor right inside the barrel.

Fewer than 200 were made during the war, but it had the reputation as being one of the quietest firearms ever developed. The carbine was used by allied troops in several covert missions, including the assassination of two German officers during efforts to aid the French Resistance. But the de Lisle isn’t just an obscure historical footnote in WWII history, it’s also a landmark weapon in suppressor development.

The sound generated by a firearm generally comes from two sources; the rapid expansion of gases that are released when the round is ignited, and the supersonic “crack” of the bullet flying through the air faster than the speed of sound. To the human ear, the two sounds seem to happen simultaneously as one loud bang. A suppressor works on the same principle as a muffler on a car; it acts as a chamber where the gases can expand and cool as they exit the gun, thereby drastically reducing the sound. However, unless the round being fired is travelling slower than the speed of sound, the suppressor will have no effect on the sound of the bullet breaking the sound barrier. Because of this, despite what you see in the movies, firearms with suppressors usually make quite a racket, even if they’re drastically less noisy than unsuppressed guns. But the de Lisle was designed to be used at relatively close range without drawing any attention to the user, and that’s a technological feat it is more than capable of.

A couple of key factors make the de Lisle carbine one of the quietest guns made, even by today’s standards. First is the closed action. Because the bolt action carbine is manually operated, the action doesn’t open when it’s fired as it would on a semi-automatic rifle. That means the only gases escaping from the weapon are through the muzzle, which is equipped with a large suppressor. The act of chambering a fresh round is actually louder than the report of the rifle, but because it’s a bolt action, the action doesn’t cycle until the user decides to do so manually; another great feature when stealth is required.

The de Lisle carbine also fires a round that is perfectly suited for suppression; the .45 ACP. Because it’s a big, heavy bullet, the 45 doesn’t have to travel quite as fast as other handgun rounds in order to be effective. Almost all factory .45 ACP ammunition will travel at subsonic speeds. Unsuppressed, it sounds as loud as any other handgun, but with the de Lisle’s large integral suppressor, the .45 ACP becomes a truly silent weapon. 

Because of the extremely low production numbers, you won’t be finding military surplus de Lisle carbines for sale any time soon. However, since the design is based on the commonly available Enfield action, there are lots of clever gunsmiths out there who are able to build functioning replicas of the original... for the right price. Valkyrie Arms produces a few versions of the de Lisle that painstakingly replicate the original design. Special Interest Arms has taken a different approach and claims to have improved the carbine with more reliable ejection and the ability to accept unmodified 1911 magazines. Rifles from either firm will run you around $2000-2500. In addition, the ATF regulates suppressor ownership as well as rifles with barrels shorter than 16”. You can still own them, but you’ll have to fork out a one-time $200 transfer tax for each “restricted” feature. To help soften the blow, Special Interest Arms offers a version of the de Lisle with a longer barrel, so that only a single $200 tax for the suppressor is required.

The de Lisle carbine makes a great range toy, and would be fun for both novice shooters and experienced enthusiasts. Unfortunately, it’s not good for much else. The slow bolt action makes it a poor choice for self defense, and the .45 ACP round is not well suited for hunting. But if you have the cash to burn on a truly unique novelty that can fire commonly available ammunition, the de Lisle Carbine will definitely turn some heads at the range.
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4 comments
 
I saw one of these fired in a training video a couple years ago. Brilliant gunsmithing and design.
 
Surprisingly, these are legal in the UK, as long as you have the right certificate.
 
I read an article on this very rifle in "SHOTGUN NEWS" some years back. It had cutaway drawings of the integral suppression system. It was a brilliant design for its time! Unfortunately, these are getting much harder to find and if you can find one, you better be ready to shell out some serious cash!
 
That is some gorgeous custom work. I'd love to hear more about specific operations this was used on?
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