The 7X57mm Mauser (7mm Mauser, 275 Rigby) was developed by Peter Paul Mauser in 1892, based on his 8X57mm case necked down. It was quickly adopted by Spain, later by Mexico, and was purchased in large quantities by the Boer Republics in South Africa. Thus America faced the 7x57 in the Spanish-American War and the British faced it in the Second Boer War. Both were impressed by its range and accuracy and it became a popular sporting cartridge in the English-speaking world. In 1899 John Rigby renamed it 275 Rigby for the British market. Early hunters such as W.D.M. Bell and Jim Corbett used it for very large game, but it's really ideal for deer-sized game and was a favorite of Jack and Eleanor O'Connor. In America it has been largely replaced by the ballistically similar 7mm-08, but it retains a small but loyal following. Current factory loads are mild because of older (pre-98) Mausers still in use, with a 140-grain bullet at about 2680 fps standard. —
Craig Boddington