Pedersen Device

About the Pedersen Device

The Pedersen Device is a semi-automatic conversion unit that replaced the bolt of a modified M1903 Springfield rifle, turning the bolt-action service rifle into a blowback-operated, semi-automatic carbine firing a low-power .30 caliber pistol-sized cartridge. Designed by John D. Pedersen during World War I, it was issued the deliberately misleading nomenclature 'Automatic Pistol, Caliber .30, Model of 1918' to preserve secrecy. Fed by a 40-round stick magazine inserted at an angle on the right of the receiver, it was intended to deliver high-volume close-range fire across no man's land while still allowing the soldier to reinstall the standard bolt for long-range bolt-action shooting. The war ended before it could be used in combat, and almost all of the roughly 65,000 devices produced were later destroyed, making surviving examples among the rarest of American military firearms.

Demonstrated to US Army ordnance officers on October 8, 1917, the device so impressed observers that it was rushed into secret production. Pedersen reportedly stood and fired rapid semi-automatic fire from a rifle that moments earlier had been a slow bolt-action, stunning the officers present. The Armistice of November 1918 rendered the weapon's surprise-assault role moot, and it never saw combat.

Pedersen Device specifications

The Pedersen Device is not a complete firearm on its own; it replaces the bolt assembly of a specially modified rifle (the M1903 Mark I) that featured an oval ejection port, altered sear, and modified magazine cut-off. After the Armistice the US Army scrapped the vast majority of devices in the 1920s, which is why intact examples are extremely valuable to collectors.