The FF series inspired many 20mm cannon used in World War II, including the Hispano-Suiza HS.404 (adopted by the French, British and U.S. forces), the German MG FF, and the Japanese IJNAS's Type 99 cannon.

In addition to various changes needed for remote firing and cartidge ejection, the new series focused primarily on rate-of-fire.

The original "FF" used a slightly upgraded 128 gram 20x72mm round with a muzzle velocity of 600 metres per second (2,000 ft/s) at a cyclic rate of 520 rounds per minute, almost double that of the original F and AF models.

In the 1930s, Marc Birkigt designed an entirely new gas-operated cannon with a locked bolt, the HS.404, which became one of the best 20 mm weapons of the war.

Ikaria Werke in Germany started production of the FF F with a slightly more powerful 20x80mm round as the MG FF, but later introduced a new mine shell round which was lighter and improved velocity.