8×68mm S - Cartridge Dimensions

Cartridge Dimensions

Extremely thick brass results in 'only' 5.58 ml (86 grains) H₂O cartridge case capacity for the 8x68mm S. A rare feature of this German rimless bottlenecked centerfire cartridge design is that it has a slightly rebated rim (P1 - R1 = 0.3 mm). A sign of the era in which the 8x68mm S was developed are the gently sloped shoulders. The exterior shape of the case was designed to promote reliable case feeding and extraction in bolt action rifles, under extreme conditions.

8x68mm S maximum C.I.P. cartridge dimensions. All sizes in millimetres (mm).

Americans would define the shoulder angle at alpha/2 ≈ 14.53 degrees. The common rifling twist rate for this cartridge is 280 mm (1 in 11.02 in), 4 grooves, Ø lands = 7.89 mm, Ø grooves = 8.20 mm, land width = 4.40 mm and the primer type is large rifle magnum.

According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) guidelines the 8x68mm S case can handle up to 440 MPa (63817 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 American .325 WSM cartridge introduced in 2005 is probably the closest ballistic twin of the 8x68mm S. The .325 WSM is considerably shorter and fatter and has a more radical rebated rim (P1 -R 1 = 0.51 mm), much steeper shoulder angle (70 degrees / 35 degrees for Americans) and a shorter neck (7.82 mm). This makes the 8x68mm S case with its 9.11 mm long neck better suited for loading long heavier bullets and due to its sleeker exterior shape bound to cycle more reliably in bolt action rifles in extreme situations.