Some real figures--
The Mexican 1910 has a front ring that's 1.270 in diameter. A CZ 527 is 1.200.
The difference between these parts and the rifle above is time and money.
Mauser used two barrel shank diameters: 1.1" and .980. True 'Small ring' actions have a small shank and a small front receiver ring. The KAR 98s have a large shank in a small ring and is barely thick enough to drill and tap. They have a BAD heat-treat reputation.
All the Mauser true small rings are very desirable for custom rifles, especially the 7x57 length G33-40, VZ-33 and 1910 Mexican. The most desirable of all small rings is the Kurtz action which was especially made for the .250 Sav and is considerably shorter than any other Mauser made. They're all small ring and many times have a square rear bridge.
The first pictures on this page
http://www.hallowellco.com/bolt_action.htm shows a Kurtz action that's had considerable work done on it.