The 7.5×54mm French MAS has an uncommon 12.39 mm (0.488 in) breech and breechface diameter, and it has ballistics comparable to the 7.62×51mm NATO/.308 Winchester round.

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.

However it lasted only until 1929 when it was replaced with the slightly shorter 7.5×54mm MAS 1924-M29, due to the original cartridge being very similar in size and appearance to the German 7.92×57mm Mauser.

As a result, a French soldier could potentially chamber a 7.92×57mm cartridge (which were also in fairly widespread use by the French military, e.g. in machine guns obtained as war reparations) and cause a massive failure if fired in a rifle designed for the less powerful and smaller calibre 7.5×57mm.

However, fortress machine guns in the Maginot line used 235 mm twist rate since they were designed for a heavier, Mle 1933D bullet.

[6] (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.

[4] regulated countries are currently (2017) proof tested at 475.00 MPa (68,893 psi) PE piezo pressure.

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.

[citation needed] In countries where restrictions prevent civilian hunting use of firearms chambered in Military cartridges still considered "War Materiel" like the 7.5×54 French MAS, owners of surplus military firearms may have them changed to a different, non-military cartridge.

The easiest and usually the cheapest way is to rechamber the firearm to something that uses the same barrel and bore, but removes the old military chamber during the re-chambering process.