Type Rifle In service 1929–1990 | Designer MAS | |
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Wars World War IIFirst Indochina WarAlgerian WarSuez CrisisVietnam WarShaba II | ||
The 7.5×54mm French or 7.5 French (designated as the 7,5 × 54 MAS by the C.I.P.) is a rimless bottlenecked rifle cartridge. It was developed by France as an update to the 7.5×57mm MAS mod. 1924 cartridge. It replaced the obsolete 8×50mmR Lebel round used during World War I.
Contents
The 7.5×54mm French chamber has an uncommon 12.39 mm (0.488 in) breech diameter and is ballistically comparable to the 7.62×51mm NATO/.308 Winchester round. The 7.5 French cartridge is somewhat similar in appearance to the slightly longer and thicker 7.5×55mm Swiss GP11 round but users should never try to interchange the two rounds.
History
By the end of World War I the French Army realized that it needed to update its once revolutionary, but now obsolete, 8 mm Lebel ammunition. Due to the demands of mass production of the 8mm Lebel round during World War I it was not able to do so until the war had ended in November 1918. Six years later, the 7.5×57mm MAS cartridge was introduced in 1924. However it was soon replaced in 1929 with the slightly shorter 7.5×54mm MAS 1924-M29 . Two bullet variations were tested for military use at the time, the 1924 C and 1924 D, the former being lighter than Balle 1924 D.
The French Army chose to adopt "light ball" 9.0 grams (139 gr) Balle C flat base spitzer bullet ammunition for universal service in the MAS-36 and MAS-49 rifles as well as in the Mle 1924-29 machine rifle. The "heavy ball" 12.35 grams (190.6 gr) Balle 1929 D featured a boat-tailed spitzer bullet and had limited specialized use in automatic weapons like the Mle 1931 F and the FM Mle 1924M29 machine guns.
Common variations of the 7.5×54mm French military round are: armor-piercing (Balle AP), tracers (Balle A), incendiary (Balle I), gallery practice and blank. The 7.5mm×54 French round is still classified in France as war material.
Cartridge dimensions
The 7.5×54mm French has 3.76 ml (58.0 grains H2O) cartridge case capacity. The exterior shape of the case was designed to promote reliable case feeding and extraction in bolt action rifles and machine guns alike, under extreme conditions.
7.5×54mm French maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm).
Americans would define the shoulder angle at alpha/2 = 20 degrees. The common rifling twist rate for this cartridge is 270 mm (1 in 10.63 inches), 4 grooves, Ø lands = 7.57 mm (0.298 in), Ø grooves = 7.85 mm (0.309 in), land width = 3.70 mm (0.146 in), and the primer type is Berdan or Boxer Large rifle.
According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) rulings the 7.5×54mm French can handle up to 380.00 MPa (55,114 psi) Pmax piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. This means that 7.5×54mm French chambered arms in C.I.P. regulated countries are currently (2017) proof tested at 475.00 MPa (68,893 psi) PE piezo pressure.
The American 7.62×51mm NATO/.308 Winchester cartridge, which succeeded it in French military use, offers similar ballistics compared to the 7.5×54mm French.
Availability
The original French-made military ammunition tends to be scarce in the United States and is often corrosive and always Berdan-primed. The pressure is rated at around 40,000 CUP or about 295 MPa (42,800 psi). The original military brass is highly prone to head separation when reloaded above 40,000 CUP. The reason is that the military Berdan-primed cartridges were made with a specially scored internal annular groove between the head and body to purposely weaken the case and prevent reloading by enemy forces, which had apparently been a problem at one time for the French when they occupied Morocco. MAS 36 bolt action rifles are capable of handling pressure much higher than 40,000 CUP.
Reloadable Boxer-primed 7.5×54mm French cartridge cases can be produced by reforming 6.5×55mm brass with commercial case forming dies. The ammunition manufacturer Prvi Partizan has brought onto the U.S. market freshly manufactured reloadable non-corrosive 7.5×54mm French ammunition loaded with a 9.0 grams (139 gr) bullet that meets the specifications of the original round.