The MAC-58 was a version of the French AA-52 machine gun chambered in .50 BMG instead of 7.62×51mm NATO. A few prototypes were tested and one retained for preserial production, but it never reached production due to the large quantity of US M2 Browning machine guns already in service with the French armed forces.
By DM 46 ST / MRA of 23 September 1950, the Manufacture d'Armes de Châtellerault receives a provisional program for making the study of a 12.7 mm machine gun to replace the Browning M2. Only the power mode of the weapon was imposed. Other features were left to the initiative of consulting firms involved in Mulhouse, Châtellerault and Saint Etienne. A Chatellerault, the study was entrusted to Davail Technician under the orders of Chief Engineer Martin and the instigation of Directors, BMI and BMI Rabbe Nardin. It culminates in the presentation, February 12, 1956, the dimensional drawing of the weapon the Technical Department of the DEFA and the realization of a prototype. The weapon was inspired by the AA-52 general purpose machine gun whose realization shells pressed steel necessitated the use of presses of 300 and 400 tons recently implanted in the MAC. It weighed 26 kg, that is to say unless the machine gun M2 HB CAL US .50 (39 kg).
Specifications that would meet the 12.7 mm machine guns were specified in the MAC. "The weapon must: 1. be adaptable and self-vehicle light machine gun, 2. enable effective fire against helicopters or light aircraft at an altitude of about 1000m, 3. range adjusted up to 1000m and 2000m up. 4. be a weight for easy handling and especially the landing ground for shooting, 5. be a maintenance and operation easier than the machine gun of 12.7 US, 6. learn the different types of ammunition of 12.7 US regulatory (especially piercing bullet to be effective against lightly armored up to 600m). It will not be studied lookout for new shooting ground, the lookout US ideally suited. Regarding the first specification, the vehicle is currently not defined and self-LMG in the study. " The MAC should provide for 25 August 1956 at the latest, an information sheet containing the following: a) the main features of the prototypes, b) status, c) when the prototype will undergo their next experiment the Institution of Experiments Techniques Versailles. 8354/ET/MAC by letter of 23 August 1956, the MAC has sent its response to the demand for ST / ARM: 1. The route congestion sent February 16, 1956 to the first question should 2. the prototype is provided for feeding the left output of the link belt and the right by ejection from below 3. effectiveness of air target shooting identical to the 12.7 currently used in groups of Light Anti-Aircraft 4. shooting ground is set with bezel APX 806. 5. weight is comparable to that of the Hotchkiss M1914 machine gun. 27.5 kg with heavy barrel. 6. principle is based on the AA 52 with few parts 7. the gun fires cartridges NATO and French 8. it is mounted on the M3 tripod by a flexible link MAC 9. its rate is 500 to 600rpm.
Two prototypes were presented to the CABA, 30 November 1956 for a first prototype, the second was sent May 28, 1957. It contained only a few detail improvements, made as a result of tests on prototype # 1. On 27 June 1957, three machine guns were sent to complete the CABA. Two copies were for the Technical Section of the Army. The weapon was found valid in its presentation and its operating principle, but it could be mounted on all military vehicles in service because of its shape and organization (no handles rear). On December 10, 1959, the prototype No. 7 and 8 were given to the Atelier de Construction d'Issy-les-Moulineaux for adaptive trials on a circular troop transport vehicle. Ultimately, 12 prototypes were ordered in December 1956 made and experienced. The weapon remained as the prototype for the development was not considered necessary.