Pedersen Device – America’s Secret Infantry Weapon of World War I

Prototypes were also made for the M1917 Enfield and Mosin-Nagant rifles that were in U.S. service at the time.

Read on to get the full story of this amazing gadget developed by John Pedersen.

Mr. Pedersen started his demonstration by firing the Springfield rifle he brought with him.

Shown here is a modified Springfield M1903 rifle with an installed Pedersen Device. The Pedersen device was an experimental weapon attachment for the M1903 Springfield bolt action rifle that allowed it to fire a .30 caliber pistol-type cartridge in semi-automatic mode.

The mysterious Pedersen Device, attached to the Springfield Mark I. Image: SANHS

Infantry Weapons of the First World War.

The role of Q was played byJohn Pedersen, a talented firearms designer.

It was an invention indicative of the fertile minds of the time.

The Pedersen Device modified the United States Army service rifle to a semi-automatic rifle using a blowback system that fired a pistol cartridge instead of the .30-06 Springfield through the gun barrel. It was considered an improvement in weapon design for trench warfare.

The M1903 Springfield was America’s standard battle rifle at the beginning of World War I. Image: Author’s collection

Pershing also urged great secrecy around the project.

The naming ruse worked for intel purposes, but it was also functionally correct.

The magazines featured cut-outs that allowed the firer to see the number of rounds remaining.

A platoon of U.S. Army soldiers move under an artillery barrage at the German Army troops during World War I. A Renault FT tank is in the background. An officer holds a M1911 semi-automatic pistol chambered for the .45 ACP cartridge.

The Pedersen Device was planned as part of the Allies’ 1919 Grand Offensive, supported by tanks and fresh American troops. Image: NARA

Assumptions were made that Pedersens weapon would be highly effective in both defensive and offensive operations.

to an infantrymans already heavy burden.

Production of the Pedersen gear (and its ammunition) began in March 1918.

While it was not a machine gun or artillery piece, the Pedersen Device turned the bolt action rifle into a semi-automatic firearm. For trench warfare this weapon was more effective than a pump action shotgun or semi-automatic pistol.

The Pedersen Device was a radically innovative adaptation of the M1903 design. Image: SANHS

Without the Mark I rifle, the Pedersen gear has nowhere to work.

Mark I appears on the receiver.

Minus the Pedersen rig, the Springfield Mark I operates as a normal M1903 rifle.

While it wasn’t a tank or APC, the Pedersen Device was a potential game changer in no man’s land on the Western Front. General John J. Pershing wanted these for the anticipated Grand Offensive in the Spring of 1919. It gave the Allied Powers rifleman a lot of firepower.

The 40-round magazine for the small .30-18 round. Image: SANHS

More than 65 million .30-18 cartridges were made at Remington and 101,775 Mark I rifles were made at Springfield.

Pedersens concept was also considered for Americas most numerous battle rifle during World War I, the M1917 Enfield.

Neither one went into production.

The metal box magazine for the modified Springfield M1903 rifle held 40 cartridges. The cartridge was the 7.65×20mm Long also known as the .30-18 Automatic round.

The 40-round magazine was installed at a 45-degree angle. Image: SANHS

Born in Secrecy, Destroyed in Obscurity

Ultimately, the Pedersen gear never saw combat.

The Pedersen Devices, already shrouded in secrecy, were placed into storage.

Less than one hundred examples survived.

The Pedersen Device was classified information the same as any new armored car or aircraft. In the arsenal of the U.S. soldier, it would ensure domination from Fort Riley to the trench on the front line of Europe in Belgium or France.

Shown here is the Pedersen Device that was officially called the “Automatic Pistol, Caliber .30, Model of 1918” to conceal its nature should a spy discover it. Image: SANHS

Even so, John Pedersens unique genius remains, a testament to what American ingenuity can create.

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U.S. Infantry Weapons of the First World War

engineering drawing for the Pedersen Device patent application filed by John Pedersen the firearm inventor at Remington Arms

This is the engineering drawing in the patent application for John Pedersen’s device. Image: NARA

This photograph from Springfield Armory shows the complete Pedersen Device kit as manufactured by Remington Arms for the United States Army in World War I.

The complete kit for the Pedersen Device. Note the comparison of the .30-18 ammunition with the standard .30-06 cartridge at the upper right. Image: SANHS

The Pedersen Device disassembled. Image: SANHS

Metal scabbard for the Pedersen Device. Image: SANHS

The 40-round Pedersen magazine. Note the slots to show the amount of ammo remaining. Image: SANHS

U.S. Infantry Weapons of the First World War

Born in Secrecy, Destroyed in Obscurity#

U.S. Infantry Weapons of the First World War#

Born in Secrecy, Destroyed in Obscurity

U.S. Infantry Weapons of the First World War