Introduced in 1952, the AAT-52 ("Arme Automatique Transformable Modele 1952") became the standardized General Purpose Machine Gun (GPMG) of the French Army and its colonial forces worldwide. Design work was spurred by growing combat experience with a variety of foreign-born machine guns during the First Indochina War by France which resulted in a need for a French-originated solution of equal form and function to help streamline logistics, supplies and training. Design of the new GPMG fell to the storied concern of Manufacture d-Armes de Sain-Etienne (MAS) and the AAT-52 series was born, continuing service (albeit limited) in the modern French military. It was also adopted by Belgium, the Central African Republic, Ivory Coast, Ireland, Madagascar, Morocco, Niger, Somalia and others during its long service life.
As originally designed, the AAT-52 was chambered for the 7.5x54mm French rifle cartridge though the Western shift to adopt a singular rifle cartridge in 7.62x51mm NATO format revised the AAT-52 design which begat the AA 7.62mm "NF-1" designation. These quickly replaced manufacture of 7.5mm types. Despite a slight drop in muzzle velocity with the new cartridge, the machine gun was now of a more standardized form and within general NATO standards.
Design of the weapon remained largely conventional though the AAT-52 was designed around a lever-delayed, blowback action which proved a departure from the norm in the world of military machine guns. Feeding was through a 50-round, linked belt system which showed some influence from the German World War 2-era MG42 series. The AAT-52 was listed with a rate-of-fire of 900 rounds per minute with a muzzle velocity of 830 meters per second with effective ranges out to 600 meters. Maximum range was out to 3,200 meters with sighting through iron sights as standard and improved with use of optional optics for accurized ranged firing. The barrel was air-cooled which put the responsibility of barrel overheating on the gunnery crew to prevent warping and fracturing due to the intense heat generated through prolonged, sustained firing. Overall weight of the system was near 9.75 kilograms with an overall length of 1,080mm (the barrel measuring 600mm long). A carrying handle was typically affixed just aft of the barrel and assisted in barrel-changing. Management of the weapon was through a conventional pistol grip with ringed trigger unit.
As a GPMG, AAT-52 was eventually fielded in a variety of forms to suit the battlefield need. In the light machine gun support role, it was showcased with a folding bipod mounted under the barrel as well as a light barrel assembly to reduce carrying weight. A monopod can also be accepted under the stock, aft of the pistol grip for additional support when firing from the prone position. A heavy tripod with a heavy barrel combination could quickly change the AAT-52 into more of a defensive-minded, fixed machine gun. The machine gun also provide effective as a vehicle weapon, installed as a coaxial system in tank turrets (including the French LeClerc MBT) and similar armored vehicles, on pintle mounts atop open-topped, light-armored vehicles (such as armored cars) and in fixed, forward-firing mounts on strike aircraft (the Fouga Magister) and helicopters.
To date, the AAT-52 has been fielded across many notable conflicts including the First Indochina War (1946-1954), the Algerian War (1954-1962), the Suez Crisis (1956), the Persian Gulf War (1991), the Bosnian War (1992-1995), the War in Afghanistan (2001-Present) and the Libyan Rebellion (2011). The modern French Army has been replacing its stock of AAT-52 guns with other solutions since, including the Belgian FN MAG GPMG series aboard armed helicopter transports and the Belgian FN Minimi for squad support. The weapon has seen modern combat actions in recent operations in Mali involving French and local forces.
The MAC-58 was a proposed .50 BMG-chambered heavy machine gun version of the AAT-52 family which was evaluated but never produced as it would have had to compete on the world stage with the excellent and long-running American Browning M2 heavy machine gun already embedded across dozens of militaries in the world.