The FAMAS uses a delayed blowback operating system that functions best with French-specified steel-casing 5.56×45mm ammunition.
Using standard brass-casing 5.56×45mm NATO ammunition employed by other armies can create over-pressure and case ruptures in the FAMAS during extraction, which can lead to severe malfunctions.
Using incorrectly built ammunition also results in approximately two minor injuries for every million rounds fired from a FAMAS.
As a result, the French military has discreetly banned the use of foreign-produced ammunition in all French-issued FAMAS rifles.
However, fluting the chamber will completely remove these malfunctions, although the brass casings will still be deformed and will not be able to be reloaded without reshaping.

The FAMAS F1 uses a proprietary 25-round magazine.
It has a chrome-lined barrel with 1 turn in 12 inch (1:12 inch) rifling and functions best with the 55 gr (3.6 g) (M193 type) ammunition.
When using the French made 5.56 mm 55 gr (3.6 g) ammo it has a muzzle velocity of 3,150 ft/s (960 m/s).

The FAMAS G2 uses M16-type, NATO-compatible 30-round STANAG magazines.
It has a chrome-lined barrel with 1 turn in 9 inch (1:9 inch) rifling and functions equally well with both the older 55 gr (3.6 g) (M193 type) ammo and the newer 62 gr (4.0 g) (SS109 type) ammo.
When using the French made 5.56 mm 62 gr (4.0 g) ammo it has a muzzle velocity of 3,035 ft/s (925 m/s).

During training with blank ammunition, a special plug is added to the muzzle of the FAMAS.
This plug is necessary for automatic or semi-automatic blank fire operation, and functions by blocking part of the gas used in a blank cartridge.
The FAMAS uses a delayed blowback operating system that functions best with French-specified steel-casing 5.56×45mm ammunition. Using standard brass-casing 5.56×45mm NATO ammunition employed by other armies can create over-pressure and case ruptures in the FAMAS during extraction, which can lead to severe malfunctions. Using incorrectly built ammunition also results in approximately two minor injuries for every million rounds fired from a FAMAS. As a result, the French military has discreetly banned the use of foreign-produced ammunition in all French-issued FAMAS rifles. However, fluting the chamber will completely remove these malfunctions, although the brass casings will still be deformed and will not be able to be reloaded without reshaping.
The FAMAS F1 uses a proprietary 25-round magazine. It has a chrome-lined barrel with 1 turn in 12 inch (1:12 inch) rifling and functions best with the 55 gr (3.6 g) (M193 type) ammunition. When using the French made 5.56 mm 55 gr (3.6 g) ammo it has a muzzle velocity of 3,150 ft/s (960 m/s).
The FAMAS G2 uses M16-type, NATO-compatible 30-round STANAG magazines. It has a chrome-lined barrel with 1 turn in 9 inch (1:9 inch) rifling and functions equally well with both the older 55 gr (3.6 g) (M193 type) ammo and the newer 62 gr (4.0 g) (SS109 type) ammo. When using the French made 5.56 mm 62 gr (4.0 g) ammo it has a muzzle velocity of 3,035 ft/s (925 m/s).
During training with blank ammunition, a special plug is added to the muzzle of the FAMAS. This plug is necessary for automatic or semi-automatic blank fire operation, and functions by blocking part of the gas used in a blank cartridge.
FAMAS