Pedersen device

Pedersen device, officially US Automatic Pistol, Caliber .30, Model of 1918
Diagram illustrating the device
Type	Semi-automatic rifle
Place of origin	United States
Service history
In service	1918-1931
Used by	US Army
Production history
Designer	John Pedersen
Designed	1917
Produced	1918—1920
No. built	65,000
Specifications
Weight	2 lb 2 oz (0.96 kg) empty 3 lb 2 oz (1.4 kg) loaded
Cartridge	.30-18 Auto also known as the 7.65×20mm Longue
Action	Simple blowback
Feed system	40-round box magazine

During World War I, the United States secretly developed the Pedersen device attachment for the M1903 Springfield rifle that allowed it to fire a .30 caliber (7.62 mm) pistol type cartridge in semi-automatic mode. This attachment was developed to allow an infantryman to convert "his rifle to a form of submachine gun or automatic rifle" in approximately 15 seconds.

Production of the Pedersen device and modified M1903 rifles started during 1918. However, the war ended before they were sent to Europe. The contract was cancelled on March 1, 1919, after production of 65,000 devices, 1.6 million magazines, 65 million cartridges and 101,775 modified Springfield rifles.

The devices, magazines, ammunition and rifles were subsequently placed in storage, and declared surplus in 1931. To prevent them from falling into the hands of the lawless, nearly all of the stored devices were destroyed by the Army except for a few examples kept by Ordnance Department. Fewer than 100 Pedersen devices escaped ordered destruction to become extremely rare collectors' items.

Prior to the United States entry into World War I, John Pedersen, a longtime employee of Remington Arms, developed the Pedersen Device. His idea was to dramatically increase the firepower available to the average infantryman. His final design, replaced the bolt of a modified Springfield M1903 rifle with a device consisting of a complete firing mechanism and a small "barrel" for a new .30 caliber pistol like cartridge.

In effect, the "device" was essentially a complete blow-back pistol minus a receiver/grip using the short "barrel" of the device to fit into the longer chamber of the M1903 rifle. The mechanism was fed by a long 40-round magazine sticking perpendicularly out of the rifle at a 45-degree angle to the top right, and could be reloaded by inserting a new magazine. Each magazine had cut-out viewing slots facing aft so the rifleman could observe the number of unfired rounds remaining. The system required an ejection port to be cut into the left side of the M1903 rifle's receiver and the adjacent cut away to allow clearance for spent cartridges being thrown from the action. Sear, trigger, and magazine cut-off also required modifications which did not limit the ability of Mark I receivers to function in the normal bolt action mode.

Pedersen traveled to Washington, DC on 8 October 1917 to conduct a secret demonstration for Chief of Ordnance General William Crozier and a selected group of army officers and congressmen. After firing several rounds from what appeared to be an unmodified Springfield, he removed the standard bolt, inserted the device, and fired several magazines at a very high rate of fire. The evaluation team was favorably impressed. To deceive the enemy, the Ordnance Department decided to call it the US Automatic Pistol, Caliber .30, Model of 1918. Plans were put into place to start production of modified Springfields, which became the US Rifle, Cal. .30, Model of M1903, Mark I. The Army placed orders for 133,450 devices and 800,000,000 cartridges for the 1919 Spring Offensive. General John J. Pershing requested 40 magazines and 5000 rounds of ammunition be shipped with each device and anticipated an average daily ammunition use of 100 rounds per device. The use of the Pedersen Device in the 1919 Spring offensive was to be in conjunction with the full combat introduction of the M1918 Browning Automatic Rifle (BAR).