A reader who read my comments on the French Model 1935A pistol commented on its relationship to the intentionally mysterious cartridge used in the Pedersen device. The existence of the Pedersen device is well-documented, but samples are rare. It was not a pistol at all, but rather a device that replaced the complete bolt of the M1903 Springfield rifle. In place in the rifle, the device took a long, 40 round-magazine of a short .32 caliber cartridge. This gave the infantryman a means to deliver high-volume, low-recoil fire while advancing in a skirmish line. The device was quickly removable when the user needed to return the rifle to its original nature. Officially adopted in the midst of our involvement in WWI, the Pedersen device was kept secret. Many were made, but the war ended before we could deploy them and they were almost all destroyed in the post-war era.
Remington made 65 million rounds of ammo for the system and most of it was destroyed as well. But there is evidence that a carbine shooting the .30 Pedersen cartridge was demonstrated to the French in the late 20s. It is identical to the 7.62mm French Long, the cartridge used in the 1935 vintage automatic pistol and the 1938 submachine gun.