The Atelier de Construction de Puteaux (APX) (English translation: "Puteaux Construction Workshops") was a state arsenal belonging to the French Army.^[1] It was located at 8, quai national in Puteaux.

Atelier de Construction de Puteaux was in charge of making ammunition and carrying out tests. The factories also produced small and medium-sized equipment (firearms and knives), while the so-called “manufacturing” workshops produced larger equipment (artillery pieces).^[2]

Atelier de Construction de Puteaux disappeared after the Second World War, being transferred to Satory and merged with Ateliers de construction d'Issy-les-Moulineaux (AMX), which specialized in the construction of tanks and other armored vehicles.

Atelier de Construction de Puteaux had two responsibilities:

To design new weapons for the French Army. It specialized in small arms and medium caliber weapons and their accessories: such as machine guns, cannon, tank turrets, Telescopic sights for rifles, missiles etc.

And for serial production of those weapons, alone or concurrently with other factories.

• 1888 : prototype of Berthier rifle.
• 1905 : Puteaux modèle 1905 machine gun. Only a few hundred copies were made because of its many defects.^[3] It was simplified and mass produced by the Manufacture d'armes de Saint-Étienne (MAS) as the St. Étienne Mle 1907 and used in the two world wars.
• 1915 : prototype of the Fusil Mitrailleur Modele 1915 CSRG, better known as "Chauchat".
• 1918 : 37 mm semi-automatic cannon model 1918 (37 mm SA 18) for light tanks.
• 1935 : 25 mm APX modèle 1937, shortened version of the light 25 mm Hotchkiss anti-tank gun.
• 1938 : 75mm high-velocity APX gun for the ARL V 39, modified from the 75mm 1929 casemate fortress gun.
• 1969 : Rapid anti-tank weapon (ACRA).^[1]

• 1957 : firing scope of the MAS-49 rifle.

• 1934 : APX 3B turret fitted on the Panhard 178.
• 1935 : APX 5 turret mounted on the AMR 35 ZT 2 and Gendron-Somua AMR 39.
• 1936 : APX standard turret fitted on the prototype of the Hotchkiss H35, prototype of the Renault R35 and the FCM 36.
• 1938 : APX-R turret fitted on the H39 variant of the Hotchkiss H35, the Renault R35 and the Renault R40. A APX-R tank turret was planned to be mounted on the AMX 38.^[4]