[citation needed] Overall, the MAS-49 and 49/56 rifles gained the reputation of being accurate, reliable and easy to maintain in adverse environments.

The 49 and 49/56 series could also endure harsh service environments, seeing combat in Algeria, Djibouti, Indochina, French Guiana, and the Battle of Kolwezi.

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.

[citation needed]Many MAS-49/56 rifles imported as surplus into the United States were rechambered locally by Century Arms International to fire the 7.62mm NATO round.

However several user reports have noted that these particular conversions were often unsatisfactory (resulting in numerous action stoppages and misfires) due to imperfect workmanship.

Furthermore, the shortening of the barrel to allow rechambering brings the gas vent closer to the chamber hence creating a higher stress on the bolt carrier.

In addition to these Century Arms conversions, approximately 250 MAS-49/56 rifles were converted in France to 7.62×51mm NATO for use by the French National Police.

Commercial 7.5×54mm "French" ammunition made in countries other than France for current distribution has been known to produce burst fire (2 or 3 rounds at a time) because of more sensitive primers.

The direct impingement gas system was first applied in 1901 to a 6 mm (0.24 in) semi-automatic experimental rifle (the ENT B-5) designed by Rossignol for the French military.

In the AG42B and MAS systems, gas is vented from a port on top of the barrel through a small diameter tube to a hollow located on the front face of the bolt carrier.

The contained forces of the gases move the carrier to the rear against the operating spring pressure with enough momentum to open the bolt, and within a short distance the end of the tube is exposed vent to the atmosphere.

It allows for the immediate installation of a "Modele 1953" APX L 806 (SOM) 3.85 power telescopic sight by sliding it into place and then locking it in with a small pressure lever.