 A third AMX 50 project was begun in August 1951.Ten preseries vehicles were to be built by DEFA ("Direction des Études et Fabrications d'Armement", the state weapon design bureau), the first being delivered in 1953.The type was armed with a 120 mm gun, also with a 1,000 m/s muzzle velocity, in response to the perceived threat posed by the Soviet heavy tanks, such as the IS-3 and the T-10.