There is no standard Mauser '98 action. There are many variations within the category "Mauser '98".
Paul Mauser developed and patented a number of ideas that became the '98, including the magazine and ammunition clip. He developed an entire series of Mauser rifles (Models 67/69, 1889-91, 1893, 1894-95, 1896 and finally the 1898). Each was an improvement over the previous one.
Many nations adopted the Mauser concepts and the US was required to pay patent infringement payments to Mauser for the Model 1903 Springfield rifle (clip and spitzer bullet).
Adhering to the Mauser concept of internal (to the stock) magazine, controlled feeding, stripper clip, etc., the main variations include action length, receiver ring diameter, metallurgy, etc. Between manufacturers, interchangeability of parts (except for the K98k of the German military) was frequently not possible due to variations.
I fondly remember the 1950's when I could walk into gun shops and buy a WW2 Mauser rifle for $10-20 depending on condition. And, I'd have my choice of 50-100 rifles at "Ye Old Hunter" (Interarms) in Alexandria VA.
