The following information on Mauser rifles from 1895 to 1907 comes from Chapter 21 of Mauser Rifles and Pistols by W. H. B. Smith. Mauser Rifles and Pistols is also available to purchase in print.
In 1895, 1896, 1900, 1903, 1904, 1905, and 1907, various minor modifications of Mausers were made at Oberndorf, for various foreign governments. Those after 1904 differ essentially only in caliber.
During the period the Germans made wide manufacturing contacts. Arrangements were made for the manufacture of their rifles at the great F.N. plants at Herstal, in Belgium, and this firm later filled export orders when Germany was not permitted to do so.
During this period also the Mauser and the Mannlicher plants tooled up to manufacture specimens of each other’s weapons at various times. Many 1907 model Mausers for the Mexican Government in caliber 7mm, were manufactured at the Steyr works in Austria.
Spain has built rifles for her own forces and for South American export on all Mauser Systems since 1893.
The degree of interchangeability in parts in these weapons is surprising. All rifles manufactured under Mauser patents from 1893 to 1907 utilize the same bolt heads; and the bases of the respective cartridges are the same. Thus it was necessary only to make a barrel change, and a minor magazine change, in order to transform from one caliber to a larger one.
Furthermore, the case lengths of the various cartridges developed are so nearly alike that very little receiver work is necessary to convert the manufacturing machinery from an “export” caliber to one which will handle the standard German cartridge.
In 1924 and later, various European factories were tooled up to manufacture the Mauser-System rifles as modified in Germany on the Gew. 98 design. These are the same except for minor details as the Kar. 98K.
When the Germans overran Austria, Belgium, Czechoslovakia, and Poland each in its turn, they were able to utilize much of the equipment they seized since it was originally adapted to German ammunition; and were further able to put seized plants to work manufacturing arms and ammunition for their standard weapons with a minimum of difficulty. In the years of peace they had seen to it that the factories in those countries, through cooperation and subsidy (among other means) were equipped with machinery and designs of German development and selection.