7×57mm Mauser

Cartridge dimensions

The 7×57mm case holds 3.90 ml (60 grains H2O) of water. Its exterior shape was designed for reliable feeding and extraction in bolt-action rifles and machine guns under extreme conditions. The shoulder angle, as Americans define it, is alpha/2 ≈ 20.55 degrees. Common rifling has a twist rate of 220 mm (1 in 8.66 in) with 4 grooves; land diameter is 6.98 mm, groove diameter is 7.24 mm, and land width is 3.90 mm.

The primer type is large rifle. European 7 mm cartridges have groove diameters of 7.24 mm, while American 7 mm cartridges use 7.21 mm grooves. According to C.I.P. rulings, the case can handle up to 390.00 MPa Pmax piezo pressure, and in C.I.P.-regulated countries each rifle-cartridge combo must be proofed at 125% of that pressure. The SAAMI MAP is 51000 psi piezo or 46000 CUP, a lower specification in deference to Remington Rolling block rifles still in circulation.

Sporting round

The 7×57mm became popular with deer and plains game hunters due to its relatively flat trajectory and manageable recoil. Its fast twist rate allows it to fire long, heavy bullets with high sectional density, offering good penetrating ability. This made it popular in Africa, where ivory hunter W.D.M. "Karamojo" Bell used 1893 pattern 7×57mm military ball ammunition in Rigby Mauser 98 rifles to shoot about 800 African elephants, relying on the 11.2 g long round-nosed military full metal jacket bullets for penetration. The cartridge was also favored by Eleanor O'Connor, wife of hunter Jack O'Connor, who used it on hunting expeditions worldwide.

Jack O'Connor remarked that he had seen more game killed with fewer shots from this cartridge than any other. Though less popular today, the 7×57mm is still produced by major ammunition manufacturers and many modern rifles are chambered for it; it is more popular in Europe than in the United States. Indian hunter Jim Corbett used a .275 Rigby-made Mauser 1898 sporting rifle to kill the man-eating Leopard of Rudraprayag in May 1926. The cartridge handles a wide range of projectile weights, is easy to reload, has mild recoil, and is accurate; some metallic silhouette shooters use it.

Military use

The Kingdom of Spain adopted the Mauser Model 1893 rifle chambered for the 7×57mm Mauser cartridge. The original loading used an 11.2 g round-nose full-metal-jacketed bullet at about 700 m/s with 2744 J muzzle energy from a 740 mm barrel. These ballistics provided a fairly flat trajectory and excellent penetration with modest recoil.

The cartridge's military qualities were demonstrated in the Spanish–American War of 1898, when 750 Spanish troops defending San Juan and Kettle hills inflicted over 1,400 casualties on approximately 6,600 attacking American soldiers. A U.S. board of investigation concluded the casualties were primarily due to the superior firepower of the Spanish Model 1893 Mauser rifles. During the Second Boer War, British authorities re-evaluated rifle and ammunition design after facing Boer sharpshooters armed with Mauser Model 1893 and 1895 rifles firing 7×57mm rounds, which outranged the .303 British cartridge in accurate long-range fire.

Military ammunition

The oldest 1893 pattern military ball ammunition used an 11.2 g long round-nosed bullet at 670 m/s with 2514 J muzzle energy from a 589 mm barrel, with a maximum range of 3250 m. In 1913, Spain issued a redesigned cartridge with a 9 g spitzer bullet at 850 m/s with 3251 J muzzle energy from a 589 mm barrel, achieving a maximum range of 3700 m; reverse engineering indicates a G1 ballistic coefficient of approximately 0.33. Later military ball ammunition used a 10.5 g spitzer boat-tail bullet at 750 m/s with 2953 J muzzle energy from a 589 mm barrel, with a maximum range of 5000 m; reverse engineering indicates a G1 ballistic coefficient of approximately 0.54.

Did You Know?

• The 7×57mm Mauser served as the parent case for the 6.5×57mm Mauser, 5.6×57mm, .257 Roberts, 6mm Remington, and 6×57mm Mauser.