6.5×57mm Mauser

The 6.5×57mm Mauser (designated as the 6,5 × 57 by the C.I.P.) is a smokeless powder rimless bottlenecked centerfire rifle cartridge developed by Paul Mauser and introduced in 1893–94.

Overview
The 6.5×57mm Mauser was designed and introduced by Mauser in either 1893 or 1894 for use as a sporting cartridge, the cartridge was created by necking down the 7×57mm Mauser.

The 6.5×57mm Mauser never saw military service with any power, but it influenced the design of a number of 6.5mm military cartridges such as the 6.5×55mm Swedish and the 6.5×58mm Vergueiro. Several wildcat cartridges have subsequently been created from the 7×57mm Mauser with almost identical calibre bullets,such as the .257 Roberts, but are not interchangeable. The .256 Gibbs Magnum was created by reducing the neck of the 6.5×57mm Mauser by 2 mm.

One famous user of the 6.5×57mm Mauser was Pete Pearson, who used a rifle in this calibre for hunting in Africa. Pearson typically used his .577 Nitro Express double rifle for hunting dangerous game, but on occasion he did use the 6.5×57mm Mauser to hunt dangerous game up to and including elephant.

6.5×57mmR Mauser rimmed variant
The 6.5×57mmR Mauser (designated as the 6,5 × 57 R by the C.I.P.) is a rimmed variant of the 6.5×57mm Mauser. The rimmed variant was designed for break-open rifles and is almost identical to the rimmless variant except for the rim and a significant lower Pmax piezo pressure.