This is part of an artical I wrote for the NZ G&H in early 2010 when I was in the grips of 7x57 fever and building a custom arround the this wonderfull cartridge. A couple of edits to clarify only but I had to correct the OP as the 7.9x57 was a commission design and not a asuer cartridge.
The 7x57.
The 7mm Mauser and the 275 Rigby.
It was in 1892 that the cartridge known by the first two of these three names was
developed, and although all three are the same and interchangeable, it would be 15 years
before Rigby, as Mauser's British agent, adopted it as the 275 in 1907. None then knew of
the fame to come for it, first as a military round, then with its world wide acceptance as a
hunting round. Again no-one would have foreseen its importance as the parent and
instigator of a whole slew of future cartridge developments. Before then of course, the
French Lebel started the modern era in 1886, with the introduction of smokeless powder in
its small-bore 8mm cartridge, making the rest of the world’s military small arms obsolete.
In 1888 the British gave us the 303 although it was loaded with compressed black powder
until 1892 when the switch to smokeless was effected. Germany's first smokeless round was
the 7.9x57 cartridge, (8mm Mauser) and originally adopted in a modified Mannlicher style
M88 Commission Rifle. ( The 7.9x57 cartridge was designed by the commision members who were responsible the M88 comission rifle) There were numerous rifle improvement made untill 1898, when, with the introduction of Mauser’s latest improved rifle design, development was complete and this action has been the lodestone for gunsmiths and manufacturer’s alike the world over ever since.
But it was the Mauser designed 7x57, developed and first released in a Mauser rifle, pattern of 1889
that was to set the world alight. In 1893 an improved design was chambered for the 7mm
cartridge and became the military mainstay of Spain, (in fact it is still sometimes referred to
as the Spanish Mauser in the U S and for good reason). It was also adopted by many
Latin-American and some European governments for their Military's, thus beginning its
world-wide distribution and acceptance first in the battle fields and then in the hunting
fields. It may have been the most widely distributed military and sporting cartridge in its
day, rivaled only by the 303 of the British Empire.
The Americans faced the Spanish in Cuba who were armed with 1893 Mausers
chambered in 7x57 Mauser, (as were the Boer's in their struggle against the British ) during
the Spanish-American war. The 6600 US troops attacked up San Juan Hill with their single
shot 45-70 and slow to load, 30-40 Krag repeater and were to lose 1400 men to the 700
Spanish on top in fortified positions armed with the 1893 bolt action Mauser, with a clip fed
magazine. After the bloodshed was over this led directly to the Americans scaling up the
7x57 to become the 30-03, later morphing into the 30-06. This round has been the basis
for in-numerable 'new' rounds, so it can be seen how influential the 7x57 has been when
you consider the number of cartridge developments it has been the foundation for.