Db 14 Pedersen device
The Pedersen device was developed for World War I and converted a rifle into a semiautomatic carbine. NRA Sporting Arms Museum

Today’s Blast from the Past focuses on the Pedersen device, a conversion unit intended to turn a rifle into a semiautomatic carbine to increase firepower in the trenches of World War I. Remington employee John Pedersen was a gifted gun designer who invented the original Model 51 pistol, the Model 10 pump, and, in collaboration with John Browning, the Model 17 pump, which would become the Ithaca 37 once its patent expired.

The device that bears his name was supposed to be his contribution to the WWI effort but it arrived too late. The requirements of trench fighting gave rise to the submachine in WWI, where compact firepower became more important than long range accuracy. The Pedersen device didn’t make rifles any more compact, but it increased their firepower from five bolt-action shots to 40 semiautomatic rounds.

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The Pedersen device increased firepower from 5 shots with a bolt-action rifle to 40 semiauto rounds. NRA Sporting Arms Museum

The device was chambered for the rimless .30/18 auto pistol cartridge, also known by its French name of 7.65x20mm Longue. It was a pretty mild cartridge, firing an 80-grain bullet at a velocity of just 1300 fps. Essentially, the Pedersen device was a blowback action that could be fitted into the receiver of an ’03 Springfield very quickly and without tools. You removed the regular bolt and slid on the Pedersen device. There was a short barrel section that fit into chamber of the rifle. Pedersen himself made a top-secret demonstration of the device to a group of officers and congressmen in the fall of October 1917. He began by firing the rifle normally, using the bolt and standard ammunition, then pulled the bolt out, threw in the semiauto conversion, and blazed away.

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Here, the Pedersen device is shown inside its carrying case. NRA Sporting Arms Museum

It was a huge hit, and when General Pershing saw it in France, he demanded it. The ’03 Mark I was designed to be used with the device, and it featured ejector ports cut in the receiver and stock. The device would have been issued in a metal case, with magazines in another pouch, so soldiers could almost instantly convert their rifles from long range and accurate to short range and high rate of fire quickly in the field. In a way, it was the precursor of the assault rifle since it had both short range firepower and longer range capability. Over 160,000 were made, but arrived too late for the war. After a period of storage, the Army decided they were obsolete and nearly all were destroyed. Only about 100 Pedersen devices survive, including this one in the NRA Sporting Arms Museum at Bass Pro Shops in Springfield, Mo.