The problem with most, if not all military Mauser is the steel used. In modern actions such as Remington, we think in terms of Chrome Moly, usually 4140 or 4142 at around 34/36 RC hardness. The steel usually used in the military Mauser was 1030/1040. While this is a steel that will respond to a heat treat, the properties obtained are sub standard compared to a true alloy steel.
The usual practice was to do a case hardening, which process used varied from Country to Country. While this case hardening did impart a good wearability, it did little to enhance the properties of the parent steel in terms of tensile and yield strength.
PO Ackley did quite a bit of testing on the various military actions from WW-1 through WW-2. He tested them to destruction. The Mauser, the various ‘03 Springfield variants, the Caricanos and the like were found to be perfectly suitable for the chamberings of the period which most fell into the 45,000 to 50,000 psi range. Surprisingly, by his testing methods, the Japanese Arisaka proved to be the strongest Of the lot.
These old military actions will not approach the strength level of a modern action produced from a true deep hardening steel such as the Chrome Moly variants. And they are quite a bit behind any of the actions machined fron one of the precipitation hardening Stainless Steels such as 17-4. Keep in mind, 416 IS NOT one of these.
I would not be scared to chamber one for 50,000 Psi, but not much over.