For "who used 7mm's" the answers are to be found in Ball, "Mauser Military Rifles of the World", now in its 4th Edition. Basically Spain and all South American countries apart from Argentinaand Peru. Plus China (M1895) and the Boers (ZAR, Orange Free State).
For a large ring/small ring list, see Kuhnhausen "The Mauser Bolt Actions", P.214, Mauser Action Dimension Table.
Get those 2 books and you will not only have a fairly exact answer to your questions, but a much deeper insight into "Mauserology".
Patrick
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