8×60mm S

8×60mm S

8×60mm S cartridge between .308 Winchester (left) and .300 Win Mag (right)
Type Rifle
Place of origin  Germany
Service history
In service Never issued
Production history
Variants 8×60mm RS (rimmed)
Specifications
Parent case 7.92×57mm Mauser
Case type Rimless, bottleneck
Bullet diameter 8.20 mm (0.323 in)
Neck diameter 9.08 mm (0.357 in)
Shoulder diameter 10.95 mm (0.431 in)
Base diameter 11.98 mm (0.472 in)
Rim diameter 11.95 mm (0.470 in)
Rim thickness 1.30 mm (0.051 in)
Case length 60.00 mm (2.362 in)
Overall length 83.60 mm (3.291 in)
Case capacity 4.16 cm3 (64.2 gr H2O)
Rifling twist 240 mm (1-9.449 in)
Primer type Large Rifle
Maximum pressure 405 MPa (58,700 psi)
Ballistic performance
Bullet weight/type Velocity Energy
11.7 g (181 gr) RWS DK 835 m/s (2,740 ft/s) 4,079 J (3,009 ft·lbf)
Test barrel length: 600 mm (23.6 in)
Source(s): RWS / RUAG Ammotech [1]

The 8×60mm S (the S means it is intended for 8.2 mm (.323 in) groove diameter bullets) is an uncommon rimless bottlenecked centerfire cartridge of German origin, dating back to the interbellum period between World War I and World War II. As is customary in European cartridges the 8 denotes the 8 mm bullet caliber and the 60 denotes the 60 mm (2.362 in) case length. The 8×60mm S can, due to its 83.6 mm (3.291 in) overall length, easily be chambered in standard sized Mauser 98 bolt action rifles.

History

After World War I, the Allied forces signed the Treaty of Versailles. This Treaty prohibited the use of standard military weapons and ammunition by Germany. However, civilian hunters didn't want to give up on this great round, so a new cartridge was designed by the German arms manufacturer Deutsche Waffen und Munitionsfabriken (DWM). Extending the 7.92×57mm Mauser cartridge case by 3 mm (2 mm of lengthened body plus 1 mm of lengthened neck) created the 8×60mm S. The 8×60mm S bullet diameter is 8.20 mm (.323 in) as found in the 8×57mm IS.

The new cartridge used the same bullet and therefore only the chamber of the rifle had to be modified (reamed out by 2 mm plus 1 mm of neck extension) to accommodate the slightly longer case. This operation was easily performed on Gewehr 98 and Karabiner 98k rifles.

8×60mm

Since this chamber reaming operation is also possible for earlier I-bore rifles, 8×60mm chambered rifles (without the S or any other further additions) also exist. 8×60mm rifles sport the earlier tighter 8.07 mm (.318 in) I-bore as found in the 8×57mm I.

To avoid potentially serious accidents, it is important to distinguish clearly between cartridges loaded for these two different bullet diameters, and only fire them in appropriately chambered/barrelled rifles.

Cartridge dimensions

The 8×60mm S has 4.16 ml (64 grains) H2O cartridge case capacity. A sign of the era in which the 8×60mm 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.

8×60mm S maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm).

Americans would define the shoulder angle at alpha/2 ≈ 14.1 degrees. The common rifling twist rate for this cartridge is 240 mm (1 in 9.45 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.

According to the official with C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) guidelines the 8×60mm S case can handle up to 405 MPa (58740 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.

Contemporary use

Mostly Mauser Gewehr 98 and Karabiner 98k rifles were rechambered for this caliber. Other rifles, not rarely based on the Mauser action, were chambered for this cartridge too.

The 8×60mm S offers compared to its parent cartridge, the 8×57mm IS, about 1 to 2% extra muzzle velocity due to its slightly larger case capacity and higher maximum operating pressure. This results in a flatter trajectory and better performance at longer range.

The popularity of the 8×60mm S peaked just after World War I and continued throughout the 1930s and 1940s. Today the cartridge is almost obsolete. No or very few rifles are produced for this round. Only two mainstream manufacturers (RWS and Prvi Partizan), along with some other smaller companies like Nolasco and Sologne, continue to produce the cartridge for hunting.

Loaded with short light bullets it can be used on small European game like roe deer and chamois. Loaded with long heavy bullets it can be used on big European game like boar, red deer, moose and brown bear. The 8×60mm S offers very good penetrating ability due to a fast twist rate that enables it to fire long, heavy bullets with a high sectional density. The 8×60mm S can be used in countries which ban civil use of former or current military ammunition. The 8×60mm S's rimmed sister cartridge, the 8×60mmR S, is also not popular in central Europe for the same reasons as the 8×60mm S.

The 8×60mm S is very popular in European countries like France where the possession of rifles in their original military caliber is tightly regulated: It allows French licensed gun owners to possess rifles based on the Mauser Gewehr 98 system under the less constraining "hunting rifle" category.

The also-rare 8×64mm S cartridge offers a comparable rechambering option for Mauser Gewehr 98 and Karabiner 98k rifles sporting 8 mm S-bores. Due to its larger case capacity the 8×64mm S chambering offers better ballistic performance than the 8×60mm S.

Handloaders can also produce this round, by altering a .30-06 Springfield case and using a standard 8 mm bullet. Prvi Partizan is a major supplier of brass components for European 8×60mm S Handloaders.

See also

References

  1. ↑ RWS Ammunition Ballistic Data & Application Consultant

External links

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