The 8x57 JS (also known as 8mm Mauser or 8mm Mauser JS) is a popular rifle cartridge with a rich history. It was developed by the German military in the late 19th century and became one of the most widely used military cartridges of the early 20th century.

The "8x57" refers to the cartridge's caliber, which is approximately 8mm (or 0.323 inches) in diameter. The "JS" stands for "J" (Infanterie or Infantry) and "S" (S-patrone or pointed bullet) and denotes the specific loading and bullet type used by the German military.

The 8x57 JS cartridge has a rimless, bottlenecked design with a relatively long case and a moderate taper. It has been chambered in various rifles, including the famous Mauser rifles and other military rifles of the time. The cartridge has a reputation for its versatility, power, and accuracy.

The original military loading of the 8x57 JS used a 198-grain, full metal jacket (FMJ) or pointed bullet with a muzzle velocity of around 2,500 to 2,700 feet per second. It was effective for medium to long-range engagements.

Today, the 8x57 JS is widely used in civilian shooting and hunting. It is available in various bullet weights and configurations, including soft point (SP), hollow point (HP), and expanding hunting bullets. The cartridge is known for its excellent performance on medium-sized game, such as deer, boar, and similar-sized animals.

It's important to note that there are different variations and chambering of the 8x57 cartridge, including the 8x57 JRS (rimmed) and the 8x57 IS (also known as 8mm Mauser Export), which may have slightly different dimensions and loadings. Always consult the specific markings on your firearm and refer to reputable sources for accurate information on the appropriate ammunition for your rifle.