My Miller & Val Greiss hammer drilling is marked 8.8mm/72 (The R is not marked). Dimensions via a cerro-safe cast are proper for the 9.3x72R. An unmarked hammerless drilling proofed 1907 (So Marked) is stamped 172.28/59. Except for the 1mm length difference chamber is proper for the 8x58R Sauer. I have also seen this round labeled as the 8x58½. 172.28 is .300" cal, which seems tight for even a .318" bullet, especially the steel jacketed one for which it is proofed. I think this simply meant it accepted the 172.28 plug gauge but not the 156.14 one (.310"). I do not recall present bore dia, but it was real close to the .310" & groove dia actually measures about .320" (neither .318" or .323") Both of these markings of course denote bore dia, not bullet dia. I have not really examined a lot of German made sporting rifles, but all which I have had bore dia & case length marked by the proof house.
For some 50 yrs I have been led to believe the .25-35 & 6.5x52R were the same thing. As has been noted it is a different dia than most other 6.5MM rounds, being a .25"cal. This is a bore size which is not common in Europe. I had been of the opinion that some makers had adopted the Winchester round & simply given it metric designation. I believe they likewise called the .30-30 the 7.62x52R (7.62mm is incidently .300" not .308").
Does anyone have SAAMI Specs for the pressure of the .25-35 Win. I do not believe it will be anywhere near 44K psi.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra