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 = , diameter of grooves = , land width = 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 Pmax 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. This lower specification is in deference to the Remington Rolling block rifles that may still be in circulation. Concerns regarding the early Mauser rifles such as the models 93 and 95 are misplaced, as the original ammunition issued with the M93 Spanish Mauser produced an average pressure of 50,370 CUP in those rifles. 7×57mmR (rimmed) A rimmed cartridge was developed from the 7×57mm 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. 7×57mmR 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