8x57 IS
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Image:8mm.jpg The 8 x 57 IS cartridge, sometimes mistaken with the 7.92 x 57 JS or 8 mm Mauser, was adopted in 1903 as the hitherto-used 8 x 57 I cartridge had to be upgraded for use with Maxim Machine guns. IS is an abbreviation for Infantrie, Spitz (infantry, pointed).
Until then, the 8 x 57 I had a round bullet that enabled it to fit into the tubular magazine of the converted Gewehr 71. The bullet is lighter, pointed, and also .323" in diameter instead of .318", and has also improved ballistics. The cartridge allows for far great range and accuracy. It was mainly used in the Axis rifles and machine guns; its use continues today in former Yugoslavia, and it is a very widely-used bullet in European hunting.
The bullet has the best ratio of energy compared to the weight of the powder loaded in all commercial hunting cartridges. It is tremendously popular in European hunting, especially German and Austrian, alongside the similar cartridges 6.5 x 57 mm, 7 x 57 mm and 8 x 68 S.
8 mm or 7.92 mm?
The European standards body CIP (Permanent International Commission) designates two 8x57mm cartridges, following the military practice. The 7,92x57mm I (or J) designates the original cartridge with a .318 inch diameter round nose bullet. The 7,92x57mm IS (or JS) designates the later, higher pressure cartridge with a .323 inch, 197 grain Spitzer bullet.
The American standardizing body SAAMI Sporting Arms and Ammunition Manufacturers' Institute designates this cartridge as the 8mm Mauser, also known as 8x57 JS. However the pressure limitation for this cartridge is taken from the older 7.92x57 I and is limited to 37,500 CUP (Copper Units of Pressure). This is done for safety, in case the .323 inch bullet is fired in an "I" bore (.318 inch) rifle.
Specifications
- Actual bullet Diameter: 8.2mm
- Diameter upon leaving barrel: 7.92mm
- Bullet weight: 9.98 g
- Muzzle velocity: 878 m/s
- Muzzle energy: 3857 J
