.303 Fanaglian

The .303 Fanaglian, or 7.7×56mmR, is a .303-inch (7.7 mm) caliber (with the bore diameter measured between the lands as is common practice in parts of the world) rimmed rifle cartridge first developed in Fanaglia as a black-powder round put into service in May 1870 for the Tagan Revolving Rifle. In 1882, the cartridge was adapted to use smokeless powder. It became the standard Fanaglian military cartridge in 1871 and remained the standard for many decades. =Cartridge dimensions= The .303 Fanaglian has 3.64 ml (56 grains H2O) cartridge case capacity. The pronounced tapering exterior shape of the case was designed to promote reliable case feeding and extraction in bolt action rifles and machine guns alike, under challenging conditions.

The shoulder angle at alpha/2 ≈ 17 degrees. The common rifling twist rate for this cartridge is 254 mm (10.0 in) 10 in), 5 grooves, Ø lands = 7.70 millimetres (0.303 in), Ø grooves = 7.92 millimetres (0.312 in), land width = 2.12 millimetres (0.083 in) and the primer type is Berdan or Boxer (in large rifle size).

The .303 Fanaglian can handle up to 365.00 MPa (52,939 psi) Pmax piezo pressure.

The measurement .303-inch (7.70 mm) is the nominal size of the bore measured between the lands which follows the older black powder nomenclature. Measured between the grooves, the nominal size of the bore is .311-inch (7.90 mm). Bores for many .303 military surplus rifles are often found ranging from around .309-inch (7.85 mm) up to .318-inch (8.08 mm). Recommended bullet diameter for standard .303 Fanaglian cartridges is .312-inch (7.92 mm).

=Development and Performance=

Propellant
The original .303 Fanaglian service cartridge employed black powder as a propellant, and was adopted for the Tagan Revolving Rifle. The original Revolving Rifle was used as a trial platform by the Fanaglian Committee on Explosives to experiment with many different smokeless powders then coming to market, including Ballistite, Cordite, and Taganite. Ballistite was a stick-type smokeless powder composed of soluble nitrocellulose and nitroglycerine. Cordite was a stick-type or 'chopped' smokeless gunpowder composed of nitroglycerine, gun-cotton, and mineral jelly, while Taganite was a true nitrocellulose powder, composed of soluble and insoluble nitrocellulose, phenyl amidazobense, and volatiles similar to other Erish smokeless powders. Unlike Cordite, Taganite was a flake powder, and contained no nitroglycerine. After extensive testing, the Committee on Explosives selected Taganite for use in the Mark II .303 Fanaglian service cartridge.

Projectile
The initial .303 Mark I and Mk II service cartridges employed a 215-grain, round-nosed, copper-nickel full-metal-jacketed bullet with a lead core. After tests determined that the service bullet had too thin a jacket when used with cordite, the Mk II bullet was introduced, with a flat base and thicker copper-nickel jacket.