A series of development prototypes followed until the French governent halted the programme in 1974, to test foreign rifles including the HK 33 and the FN CAL. MAS built the first prototypes, designated the MAS A1, in 1971. MAS chose a lever-delayed blowback action which removed the need for a gas system and theoretically made for a simpler, more reliable weapon. MAS carried out an ergonomic study and decided to develop a bullpup rifle. A year later, following ballistic testing the French military selected the new new 5.56x45mm cartridge.
Under the direction of Paul Tellie Manufacture d'Armes de Saint-Étienne (MAS) began work developing a new rifle in 1969. In 1967, the French Army requested a new infantry rifle to replace both the MAS 49/56 rifle and MAT-49 submachine gun. By the mid-1960s the French military had been in search of an assault rifle for a number of years with many of the major French state arsenals developing designs.
