8×64mm S

8×64mm S
TypeRifle
Place of originGerman Empire
Service history
In serviceNever issued
Production history
DesignerWilhelm Brenneke
Designed1912
Produced1912 - present
Variants8×65mmRS (rimmed)
Specifications
Parent casenone
Case typeRimless, bottleneck
Bullet diameter8.22 mm (0.324 in)
Neck diameter8.96 mm (0.353 in)
Shoulder diameter10.85 mm (0.427 in)
Base diameter11.95 mm (0.470 in)
Rim diameter12.00 mm (0.472 in)
Rim thickness1.30 mm (0.051 in)
Case length64.00 mm (2.520 in)
Overall length87.50 mm (3.445 in)
Case capacity4.51 cm3 (69.6 gr H2O)
Rifling twist240 mm (1-9.449")
Primer typeLarge rifle
Maximum pressure (C.I.P.)405.00 MPa (58,740 psi)
Ballistic performance
Bullet mass/type Velocity Energy
12.7 g (196 gr) S&B SPCE 810 m/s (2,700 ft/s) 4,166 J (3,073 ft⋅lbf)
12.7 g (196 gr) S&B HPC 815 m/s (2,670 ft/s) 4,218 J (3,111 ft⋅lbf)
12.8 g (198 gr) Brenneke TIG 848 m/s (2,780 ft/s) 4,600 J (3,400 ft⋅lbf)
14.25 g (220 gr) DWM Starkmantel 800 m/s (2,600 ft/s) 4,562 J (3,365 ft⋅lbf)
Test barrel length: 600 mm (23.62 in)

The 8×64mm S (also unofficially known as the 8×64mm S Brenneke) (the S means it is intended for 8.2 mm (.323 in) groove diameter bullets) is a rimless bottlenecked centerfire cartridge developed as a military service round for the German Army who never issued it. As is customary in European cartridges the 8 denotes the 8 mm bullet caliber and the 64 denotes the 64 mm (2.52 in) case length.

The 8×64mm is a hunting cartridge in central Europe and can due to its 87.5 mm (3.445 in) maximal overall length fairly easily be chambered in standard sized military Mauser Gewehr 98 bolt-action rifles. In such military M98 bolt actions the magazine boxes, however, have to be adapted by a competent gunsmith to function properly with the 8×64mm S cartridge, since the M98 internal magazine boxes feature an internal magazine length of 84 mm (3.31 in).