The 7.65×20mm Longue was a straight, rimless

Rim (firearms)

A rim is an external flange that is machined, cast, molded, stamped or pressed around the bottom of a firearms cartridge. The rim may serve a number of purposes, the most common being as the place for the extractor to engage...

 cartridge used in the French Modele 1935 pistols, as well as the MAS-38

MAS-38

The MAS-38 was a French submachine gun designed prior to the Second World War and used by French and German forces.It derived from a small arms development program that took place between 1918 and 1922 under the control of the Service Technique de l'Armement. A submachine gun, a light machine gun...

 submachine gun

Submachine gun

A submachine gun is an automatic carbine, designed to fire pistol cartridges. It combines the automatic fire of a machine gun with the cartridge of a pistol. The submachine gun was invented during World War I , but the apex of its use was during World War II when millions of the weapon type were...

.

The US .30 Pedersen cartridge (or .30-18 Automatic) used in the Pedersen device

Pedersen device

The Pedersen Device is an attachment developed during World War I for the M1903 Springfield rifle that allowed it to fire a short .30 Caliber intermediate cartridge in semi-automatic mode...

 was the basis for the 7.65×20mm Longue, the dimensions being identical. The French military were introduced to the cartridge when the US demonstrated the Pedersen device after the end of World War I in LeMans and again when John Browning

John Browning

John Moses Browning , born in Ogden, Utah, was an American firearms designer who developed many varieties of military and civilian firearms, cartridges, and gun mechanisms, many of which are still in use around the world...

exhibited a carbine in the same caliber in 1920.

7.65×20mm Longue ammunition was manufactured in quantity from approximately 1935 to 1960.