7×57mm Mauser The 7×57mm cartridge , also known as the 7 mm Mauser , 7×57mm Mauser , 7 mm Spanish Mauser in the USA and . 275 Rigby in the United Kingdom , was developed by Paul Mauser of the Mauser company 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 7×57mm 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 called this chambering the . 275 Rigby , after the measurement of a 7 mm rifle ' s bore across the lands . Military use . 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 " 7×57mm Mauser " and " 7×57mm Spanish Mauser " . It featured a long , round - nose , full metal jacketed bullet with a muzzle velocity of about with muzzle energy from a barreled rifle . For the late 19th century , these ballistics were impressive , and the loading provided a fairly flat trajectory combined with excellent penetration . At the same time , it exhibited relatively modest free recoil . That was a combination of attributes that made it popular with both soldiers and sportsmen alike . The qualities of the 7×57mm as a military round were shown in the Spanish – American War of 1898 . At the commencement of the American assault on the strategic Cuban city of Santiago , 750 Spanish troops defended positions on San Juan and Kettle Hills . The attacking force numbered approximately 6 , 600 American soldiers , most of them armed with then - new smokeless - powder Krag - Jorgensen rifle in . 30 - 40 Krag caliber , and supported by artillery and Gatling gun fire . Though the assault was successful , the Americans soon realized that they had suffered more than 1 , 400 casualties , nearly 20 per cent of their forces . A U . S . board of investigation later concluded that the casualties were primarily due to the superior firepower of the Spanish Model 1893 Mauser rifles . During the Second Boer War in South Africa , British authorities were obliged to re - evaluate rifle and ammunition design and tactics after facing Boer sharpshooter s and sniper s armed with Model 1895 Mauser rifles firing 7×57mm rounds with withering effectiveness , easily outranging the . 303 British cartridge as regards accurate long - range fire . The . 303 cartridge at that time was still using cordite propellant , in contrast to the Mauser ' s higher - performance ballistite type smokeless powder . The British modernized the previous . 303 British cartridge variants to the Mark 7 variant that like the 7×57mm used smokeless propellant , and updated their rifle to the Lee Enfield No . 1 Mk III . Military ammunition . The oldest 1893 pattern military ball ammunition was loaded with a long round - nosed bullet fired at a muzzle velocity of with muzzle energy from a long barrel . It had a maximum range of . In 1893 this ballistic performance made it the high - performance service cartridge champion of its day when compared to other 1893 pattern smokeless - powder cartridges such as the 8mm Lebel , . 303 British , and 8×50mmR Mannlicher . In 1913 , following the lead of French and German Army commands in developing the " spitzer " or pointed - tip bullet shape , the Spanish ordnance authorities issued a redesigned 7×57mm cartridge with a spitzer bullet ( " 7mm Cartucho para Mauser Tipo S " ) . It was loaded with a spitzer bullet fired at a muzzle velocity of with muzzle energy from a long barrel . It had a maximum range of . The new spitzer bullet style was partially responsible for the cartridge ' s improved performance as it significantly reduced air drag within normal combat ranges . After that military ball ammunition loaded with a spitzer bullet fired at a muzzle velocity of with muzzle energy from a long barrel became available . Besides a pointed nose this projectile also had a boat tail to reduce drag . It had a maximum range of . Cartridge dimensions . The 7×57mm cartridge has 3 . 90 ml ( 60 grains HO ) cartridge case capacity . The exterior shape of the case was designed to promote reliable case feeding and extraction in bolt action rifles and machine guns alike , under extreme conditions . 7×57mm maximum C . I . P . cartridge dimensions . All sizes in millimeters ( mm ) . Americans would define the shoulder angle at alpha / 2 ≈ 20 . 55 degrees . The common rifling twist rate for this cartridge is 220 mm ( 1 in 8 . 66 in ) , 4 grooves , diameter of lands = 6 . 98 mm , diameter of grooves = 7 . 24 mm , land width = 3 . 90 mm and the primer type is large rifle . European 7 mm cartridges all have 7 . 24 mm ( 0 . 285 in ) grooves diameter . American 7 mm cartridges have 7 . 21 mm ( 0 . 284 in ) grooves diameter . According to the official C . I . P . ( Commission Internationale Permanente pour l ' Epreuve des Armes à Feu Portatives ) rulings the 7×57mm case can handle up to P 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 . The SAAMI Maximum Average Pressure ( MAP ) for this cartridge is piezo pressure or 46 , 000 CUP . Although this lower specification is in deference to the purportedly weaker actions of the older Mauser 93 and 95 rifles which are still in circulation , this concern is misplaced , as the original ammunition developed for , and issued with , the M93 Spanish Mauser produced an average pressure of 50 , 370 CUP in those rifles . 7×57mm R ( rimmed ) . A rimmed cartridge was developed from the 7×57 shortly after its introduction for use in break - action rifles and combination guns . A rimmed cartridge greatly simplifies the issues of designing an extractor , particularly in a combination gun or " drilling " which must also be designed to extract rimmed shotgun shells . While various modern break - action and single - shot rifle and pistol designs have been developed that can reliably extract rimless cartridges , most of these date from the 1970s or later . While the external dimensions of the two versions are nearly identical other than the rim , there are differences in the internal design . In particular , the cartridge web , the area immediately above the rim on the rimmed version or the rebate on the rimless version , is thinner in the rimmed case , and some authorities recommend limiting the rimmed cartridge to 41 , 000 CUP because of this . 7×57mm R cartridge dimensions . All sizes in millimeters ( mm ) . Sporting round . The ballistics of the 7×57mm became popular with deer and plains game hunters . The relatively flat trajectory and manageable recoil ensured its place as a sportsman ' s cartridge . The 7×57mm 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 7×57mm rifle , when most ivory hunters were using larger - caliber rifles . Bell selected the cartridge for moderate recoil , and used 11 - gram military full metal jacket bullets for reliable penetration . Bell sectioned an elephant skull to determine the size and location of the brain , and used careful aim to ensure bullet placement in the brain . The 7×57 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 7×57mm . Though not as popular today , the 7×57mm is still produced by most major ammunition manufacturers and many modern rifles are available chambered for the cartridge . The 7x57mm round was also used by the Indian hunter and conservationist Jim Corbett to put down the infamous man - eating Leopard of Rudraprayag besides some of the other Man - Eaters of Kumaon . His writings mention using the . 275 Mauser - Rigby rifle to despatch the leopard while employing it as a secondary weapon for other man - eaters , especially tigers ( an Express 450 / 400 double - barrelled rifle being the primary ) . 7×57mm cartridge and rifle compatibility . In its original military loading , the 7x57mm cartridge produced an average pressure of 50 , 370 CUP when fired through the M93 Spanish Mauser rifle . However , SAAMI has published a Maximum Average Pressure of only 46 , 000 CUP for this round .