Envision this: It’s 1917, at the height of World War One. Over a million U.S. soldiers are stationed in France, many of them armed with the workhorse battle rifle, the M1903 Springfield. The fighting is fierce and bloody, with both sides of the conflict taking heavy casualties daily. Then one day, a firearms designer steps forward with something that could drastically tip the scales in America’s favor: a quick-to-install device capable of turning those old hunk-o-timber bolt-action battle rifles with a five-round capacity into a fearsome semi-automatic with a 40-round magazine. That invention was known as The Pedersen Device.

Where you’ve seen it:

Not on screen. At best, behind glass at a museum. If you come across one of these in your granny’s attic, treat it with care—the last one that went to auction at Rock Island Auctions fetched nearly $50,000. Though 65,000 were built, almost all of them were destroyed following the war.

History:

As is often the case during wartime, when presented with a better means of kicking your enemy’s ass, you tend to pay attention. A high-capacity, autoloading pistol-caliber rifle would be a significant advantage in the close proximity of the European trenches, and the U.S. War Department knew it. John Pedersen, a savant arms designer John Browning once called “the greatest gun designer in the world,” brought forth his idea for the rifle conversion, rattling through a couple sample magazines before the brass in a top secret demonstration. As they picked their jaws off the floor, the powers that be broke out their pens and ordered 100,000 Pedersen Devices to be fulfilled by Remington Arms. They planned to catch the Germans off guard with the new weapon in the Spring of 1919. Fortunately, the war ended shortly after production began. The device never saw frontline use, as it was later decided that a new standard rifle was the order of the day—not a retrofit like the Pedersen Device.

Design:

The Pedersen Device is essentially a conversion bolt that utilized the existing trigger mechanism and stock of the M1903 Springfield to convert the rifle to semi-automatic—firing a 30 caliber pistol round via a simple blowback mechanism. The rounds were loaded from a 40-round external magazine that protruded from the rifle at a 45-degree angle (above).

The cartridge:

The Pedersen Device fired the .30-18 Automatic, or as it was later known, the 7.65x20mm French Long cartridge (more famously used in the French Modèle 1935 pistol and this bad boy). Of the reasons the War Department had for not pursuing the Pedersen Device after the war had concluded, one was that the round (predictably) performed poorly at distances beyond 300 yards. It’s a small pistol round, after all. Another reason—and this one really cracks me up—was that it just wasn’t loud enough. They wanted a round that emitted such a mighty crack as to make the enemy cower in their foxholes, not some puny pop from a pistol. Even if you could dump 40 puny pops into the enemy in rapid succession.

The verdict:

John Pedersen truly was a clever guy, despite the fact that almost all of his military-based firearm designs were either stymied by poor timing or simply lost out to superior designs such as the M1911 and the M1 Garand. That said, he did develop what is essentially a new gun to fit an existing gun, which is not an insignificant accomplishment. Isn’t it a damn shame our government makes a habit of destroying old military surplus? It’d be great to outfit an old Springfield with one of these.

Opening photo courtesy of National Firearms Museum.