From Wikipedia, the free encyclopedia:
"The 7x57mm cartridge, also known as the 7 mm Mauser, 7x57mm Mauser, 7 mm Spanish Mauser in the USA and .275 Rigby in the United Kingdom, was developed by Mauser in 1892 and adopted as a military cartridge by Spain in 1893. It was subsequently adopted by several other countries as the standard military cartridge. It is recognised as a milestone in modern cartridge design, and although now obsolete as a military cartridge, it remains in widespread international use as a sporting round. The 7x57mm has been deservedly described as "a ballistician's delight". Many sporting rifles in this calibre were made by British riflemakers, among whom John Rigby was prominent; and, catering for the British preference for calibres to be designated in inches, Rigby's called this chambering the .275 Rigby, after the measurement of a 7 mm rifle's bore across the lands.
The Spanish military adopted a new Mauser rifle design in 1893. This took a smokeless powder centerfire cartridge with a bullet with a nominal diameter of 7 mm (0.285 in), and a case length of 57 mm - hence the names "7x57mm Mauser" and "7x57mm Spanish Mauser". It featured an 11 g (175 grain ) bullet with a muzzle velocity of about 700 m/s (2,300+ feet per second ). For the late 19th century, these ballistics were impressive. The change in bullet style, from a rounded tip to a pointed tip, was partially responsible for the cartridge's performance as it significantly reduced air drag within normal combat ranges.
The ballistics of the 7x57mm became popular with deer and plains game hunters. The relatively flat trajectory and manageable recoil ensured its place as a sportsman's cartridge. The 7x57mm can offer very good penetrating ability due to a fast twist rate that enables it to fire long, heavy bullets with a high sectional density. This made it popular in Africa, where it was used on animals up to and including elephants, for which it was particularly favoured by noted ivory hunter W. D. M. Bell, who shot 1,011 elephants using a 7x57mm rifle, when most ivory hunters were using larger-caliber rifles. It was also the favored cartridge of Eleanor O'Connor, wife of famous hunter and author Jack O'Connor. Eleanor accompanied her husband on multiple hunting expeditions all over the world, killing small and large game with the 7x57mm. Though not as popular today, the 7x57mm is still produced by most major ammunition manufacturers and many modern rifles are available chambered for the cartridge.
Due to the age and metallurgical characteristics of the rifles for which it was originally designed, many of which are still functioning, most U.S. commercially manufactured 7x57mm is loaded to lower pressures. European-produced rounds originating from C.I.P. member states are often loaded to give higher velocities and pressures, and these can only be safely used in modern rifles chambered for the 7x57mm cartridge. Older rifles may fire modern loads, but should be checked by a competent gunsmith and declared safe before being fired."
7x57mm Mauser. (2009, March 19). In Wikipedia, The Free Encyclopedia. Retrieved 21:28, March 19, 2009, from http://en.wikipedia.org/w/index.php?title=7x57mm_Mauser&oldid=278387617