8×68mm S

8×68mm S
8×68mm S cartidge case and headstamp
Type	Rifle
Place of origin	Germany,  Germany
Service history
In service	Never issued
Production history
Designer	August Schüler
Designed	1939
Produced	1939–present
Variants	8×68mmR S (rimmed)
Specifications
Case type	Rimless, bottleneck
Bullet diameter	8.20 mm (0.323 in)
Neck diameter	9.14 mm (0.360 in)
Shoulder diameter	12.15 mm (0.478 in)
Base diameter	13.30 mm (0.524 in)
Rim diameter	13.00 mm (0.512 in)
Rim thickness	1.40 mm (0.055 in)
Case length	67.50 mm (2.657 in)
Overall length	87.00 mm (3.425 in)
Case capacity	5.58 cm3 (86.1 gr H2O)
Rifling twist	280 mm (1 in 11.02 in)
Primer type	Large rifle magnum
Maximum pressure	440.0 MPa (63,820 psi)
Ballistic performance
Bullet mass/type Velocity Energy 11.7 g (181 gr) RWS DK 945 m/s (3,100 ft/s) 5,224 J (3,853 ft·lbf) 11.7 g (181 gr) RWS KS 990 m/s (3,200 ft/s) 5,734 J (4,229 ft·lbf) 12.1 g (187 gr) RWS HMK 970 m/s (3,200 ft/s) 5,692 J (4,198 ft·lbf) 13.0 g (201 gr) RWS EVO 915 m/s (3,000 ft/s) 5,442 J (4,014 ft·lbf) 14.5 g (224 gr) RWS KS 870 m/s (2,900 ft/s) 5,488 J (4,048 ft·lbf)
Test barrel length: 650 mm (25.6 in) Source(s): RWS / RUAG Ammotech

The 8×68mm S rebated rim bottlenecked centerfire rifle cartridge (the S denoting it is intended for 8.2 mm (.323 in) groove diameter bullets) and its necked-down sister cartridge, the 6.5×68mm (no S, or other modifier required), were developed in the 1930s by August Schüler of the August Schüler Waffenfabrik, Suhl, Germany as magnum hunting cartridges that would just fit and function in standard-sized Mauser 98 bolt-action rifles. This is one of the early examples where a completely new rifle cartridge (the 8×68mm S and 6.5×68mm have no other cartridge as parent case) was developed by a gunsmith to fit a specific popular and widespread type of rifle.

The German ammunition manufacturer RWS (Rheinisch-Westfälische Sprengstoff-Fabriken) introduced both cartridges commercially in the spring of 1939. With the official certification of the .375 Hölderlin and the 8.5×68mm Fanzoj this German 68 mm "family" of magnum rifle cartridges that all share the same basic cartridge case got expanded in the 21st century.

The cartridges in this German 68 mm cartridge "family" are, in the order of development:

The M 98 bolt actions and magazine boxes of standard military Mauser 98 rifles have to be adapted by a competent gunsmith to function properly with 8×68mm S cartridges, since the M98 internal magazine boxes feature an internal magazine length of 84 mm (3.31 in) and 8×68mm S cartridge cases have a significantly larger diameter than 8×57mm IS service cartridges. In properly adapted standard military Gewehr 98 or Karabiner 98k service rifles the large 8×68mm S cartridges are however praised for very smooth and reliable feeding.

The widespread availability of standard size Mauser 98 rifles and the fact that the .375 H&H Magnum cartridge and its necked down version the .300 H&H Magnum with approximately 72 mm (2.83 in) case length were too long to fit in standard sized Mauser 98 bolt action rifles makes the shorter 8×68mm S, 6.5×68mm and .375 Hölderlin interesting chambering options.