.308 Winchester

.308 Winchester is the commercial name of a centerfire cartridge based on the military 7.62x51mm NATO round. Two years prior to the NATO adoption of the 7.62x51mm NATO T65 in 1954, Winchester (a subsidiary of the Olin Corporation) branded the cartridge and introduced it to the commercial hunting market as the .308 Winchester. Winchester's Model 70 and Model 88 rifles were subsequently chambered for the new cartridge. Since then, the .308 Winchester has become one of the most popular hunting cartridges available. It is also commonly used for civilian targets, military sniping and police sharpshooting. The relatively short case makes the .308 Winchester especially well adapted for short action rifles and is easy to reload.

Cartridge dimensions
The .308 Winchester has 3.64 ml (56.0 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.



.308 Winchester 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 305 mm (1 in 12 in), 4 grooves, Ø lands = 7.62 mm, Ø grooves = 7.82 mm, land width = 4.47 mm and the primer type is large rifle.

According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) guidelines the .308 Winchester case can handle up to 415 MPa (60,190 psi) 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.

The .308 Winchester is a Delta L problem cartridge, meaning it can present unexpected chambering and/or feeding problems. The Delta L problem article explains this problem in more detail.

''The .308 Winchester and 7.62x51mm cartridges are not identical and there are minor differences in their inner case dimensions, though SAAMI does not list either cartridge as unsafe in a firearm designed for use with the other. ''

The .308 Winchester as a parent case
Several more cartridges have been developed using the .308 Winchester as a parent case, some becoming very popular for hunting, particularly in North America. These would be the .243 Winchester, the .260 Remington (aka 6.5-08 A-Square), the 7mm-08 Remington, the .338 Federal, and the .358 Winchester (aka 8.8x51mm). In 1980, two rimmed cartridges based on the .308 Winchester were introduced for use in the Winchester Model 94 XTR Angle Eject rifle; the .307 Winchester and the .356 Winchester.