The MAS-49 arrived after a series of small, distinct design improvements. Today, this might be termed spiral development, where small elements are changed with successive models, rather than large significant changes. The principles of French semi-automatic rifle evolved from the prototype MAS-38/39 and the MAS-40, which entered limited service in March 1940, to the MAS-44, and minor models 44A, 44B and 44C. Although 50,000 MAS-44 rifles were ordered in January 1945, only 6,200 were delivered to the French Navy. The MAS-49 was formally adopted by the French Army in July 1949. As a service rifle, it replaced the diverse collection of aging bolt-action rifles (MAS-36 rifle, Lee Enfield No4, U.S. M1917 and K98k) that were in French service after the end of World War II. It saw significant service with French troops in the latter stages of the First Indochina War, as well as during the Algerian War and the Suez Crisis.
An improved version called the MAS-49/56 was introduced in 1957 and incorporated lessons learned from service in Algeria, Indochina, and the Suez Crisis. The rifle was shortened and lightened to improve mobility for mechanized and airborne troops, and a knife bayonet was added. The MAS-49 built-in rifle grenade launcher was replaced by a combination compensator/rifle grenade launcher that fired NATO-standard 22mm rifle grenades.
Attempts were made to replace the MAS-49, in the form of the MAS-54 and the FA-MAS Type 62, both 7.62x51mm NATO battle rifles, but neither were successful. The MAS-49/56 ended production in 1978 and was replaced with the 5.56x45mm NATO caliber FAMAS bullpup assault rifle. The MAS-49/56 was withdrawn from service in 1990. Whereas only 20,600 MAS-49 were manufactured, the MAS-49/56 was mass-produced, attaining a total of 275,240 rifles issued between 1957 and 1978.
The direct impingement gas system was first applied in 1901 to a 6mm semi-automatic experimental rifle (the ENT B-5) designed by Rossignol for the French military (by definition, the direct impingement system lacks a gas piston). Although several experimental prototypes using a tilting bolt and direct impingement had been tested by MAS since 1924, the immediate precursor to the MAS 7.5mm semi-automatic rifle series is the MAS-38/39. It was successfully tested in March 1939, just before World War II, and followed in May 1940 by the nearly identical MAS 1940. Some two years later in 1942, the Swedish armed forces adopted a direct impingement semi-automatic rifle: the AG-42 Ljungman. Following which the M16 rifle was also placed into service with the U.S. Army in 1963. It was based on a direct impingement gas system, which had been designed by Eugene Stoner in 1955. As to the MAS-49 system, it vents gas taken on top of the barrel and pipes it directly into an open cylindrical hollow located in front and on top of the bolt carrier. The system has the advantage of not depositing gas fouling on the bolt itself, a separate part located underneath the bolt carrier. All the French MAS 7.5mm semi-automatic rifles mentioned herein feature a rear locking tilting bolt, as on the M1895 Colt-Browning machine gun, the Browning Automatic Rifle (1918), the MAS-1924 to MAS-1928 experimental semi-auto rifles, and the Russian Simonov SVT-38 (1938) and SVT-40 (1940) rifles.
The same 10-round detachable magazine fits the MAS-44, MAS-49 and MAS-49/56 rifles. The earlier MAS-40 (1940) rifle had a 5 round magazine within the receiver, as on the bolt action MAS-36 rifle. Lastly, the MAS-44, MAS-49 and MAS-49/56 are all equipped with a rail on the left side of the receiver. It allows for the immediate installation of a "Modele 1953" APX L806 (SOM) telescopic sight by sliding it into place and then locking it in with a small pressure lever. The MAS-49 and MAS49/56 are capable of consistently hitting individual man-size targets up to 400 meters with the adjustable peep sight and up to 800 meters with the APX 806L telescopic sight. The bore is counter sunk at the muzzle to protect the rifling and preserve accuracy. The barrel is freely floating.
The MAS direct impingement design reduced the number of bolt moving parts to only six: the bolt carrier, then the rear locking tilting bolt which carries the extractor, the ejector and the firing pin, and lastly the recoil spring. It takes only a few seconds to disassemble the entire bolt mechanism for cleaning. The MAS-49 had a reputation for reliability in conditions of poor maintenance, sometimes being cleaned with nothing more than rags and motor oil. The rifle could also endure harsh service environments (MAS rifles saw service in Algeria, Djibouti, Indochina, and French Guiana).
MAS-49 rifles produced for Syria differed slightly from the French service model by having a spike bayonet identical to that of the MAS-36.