7.92×57mm Mauser

The 7.92×57mm Mauser (designated as the 8mm Mauser or 8×57mm by the SAAMI and 8 × 57 IS by the C.I.P.) is a rimless bottlenecked rifle cartridge. The 7.92×57mm Mauser cartridge was adopted by the German Empire in 1903–1905, and was the German service cartridge in both World Wars. In its day, the 7.92×57mm Mauser cartridge was one of the world's most popular military cartridges. In the 21st century it is still a popular sport and hunting cartridge that is factory-produced in Europe and the United States. The parent cartridge, upon which the 7.92×57mm Mauser is based, was adopted by Germany in 1888 as the Patrone 88 (cartridge 88) or M/88 (along with the Gewehr 1888 service rifle). It was a first-generation smokeless propellant cartridge designed by the German Gewehr-Prüfungskommission (G.P.K.) (Rifle Testing Commission), as the new smokeless propellant introduced as Poudre B in the 1886 pattern 8mm Lebel had started a military rifle ammunition revolution. The M/88 cartridge was loaded with of single-base (based on nitrocellulose) smokeless powder and a relatively heavy, , round-nosed ball bullet with a diameter of . The M/88 bore originally had lands diameter and grooves diameter. The M/88 barrel bore specification was changed by 1894–1895 to lands diameter and grooves diameter to improve accuracy and reduce barrel wear in M/88 chambered arms. German government driven efforts to further improve on the performance of the military M/88 ammunition and the service arms in which the M/88 was used after several development steps eventually resulted in the official adoption on 3 April 1903 by the Gewehr-Prüfungskommission of the dimensionally redesigned 7.92×57mm Mauser chambering. Besides the chambering, the bore (designated as "S-bore") was also dimensionally redesigned because the new bullet with a shorter cylindrical part had reduced bearing surface, which necessitated increasing its diameter and deepening barrel grooves (as a result the new cartridge was not fully interchangeable with the old one).