How many out there ? A post on NE forum says Corbett's presentation Rigby was on this action in .275 .
Speed's book on Original Mauser sporters says the factory only used this action for a short while but no reference to numbers made .

That’s a good question. To go along with it, how many were commercial and military, how many were large ring small thread and large ring large thread, and how many were short ring and long ring? The variations were many. Most early 275 Rigby’s seem to have been built on the large-long ring small thread commercial intermediate action. The 1903 Turk and 1909 Peruvian are good examples of military versions of these action, but with some differences like stripper clip hump shape/height, thumb notch shape, and guard bow shape. I would love to have a 1909 Peruvian restyled to more resemble an early commercial intermediate action, and then used by someone like DPCD or Mike McCabe to create a Rigby clone. I’m in the college years with my kids, however.

I have a 1937 comm. Oberndorf 7x57 built on the large ring small thread (intermediate) action. The bolt is 6.16" The large ring is extended to the front. Action screw spacing is same as standard. Large ring Mauser. I also have Turk military that is the same basic action with extended ring (toward front) and stripper hump. I don't know if this helps, just sayin'. I believe most comm. Oberndorf 7x57s were built on this action, maybe left overs from 1909 Peruvian contract.
Dave