ARL V39 with the canon in retracted position
In the mid of 1935 France started the development of the new assault self propelled gun. Two companies responded with their suggestions. Somua (Société d'Outillage Usinage Mécanique et d'd 'Artillerie) started the work on a project that was to become Somua SAU S40, and ARL (Atelier de Construction de Rueil0 was developing ARL 39V prototype.
ARL 39. Hevily relied on the parts developed and used by the Char B1 tank. Frontal armor had maximum armor thickness of 50 mm. Main armament was 75 mm APX gun, a modification of the model 1292 de Casemate gun originally developed for fortifications. Gun had a semi-automatic breech, automatic charging machine and very odd an unusual feature. It’s main gun could be retracted inside the hull to decrease the vehicle length. Secondary equipment was consisted of 7.5 mm caliber machinegun placed in the small turret on the roof. A similar configuration as with the competing Somua SAU-40 project. The development was officially finished in 1938, and army field trials were conducted between 23 – 25 march 1939. The army was satisfied with the performance of the new vehicle approved the start of the serial production. Numbers vary from source to source, but apparently between 72 and 80 vehicles were ordered in the first series, together with 24 command vehicles. Fall of France stopped all production plans, and only two prototype vehicles were built. Both of them were evacuated to Marocco, but their fate remained a mystery.