Let’s discuss actions first. In the 50’s, Spain rebarreled many type 93 rifles from 7X57 to 7.62 NATO The 1893 action was fitted out for Spain as long rifles, short rifles and carbines. Although different model numbers may be assigned such as 1893, 1916, model 95 and Guardia Civil 1916 the action type is identical. Initial rifle production was carried out by Mauser and Ludwig Lowe in Germany, later the rifles were made under license in Spanish arsenals. While the German guns display better fit & finish, German and Spanish made guns are about equal in strength.
Recall we said earlier that Spain rebarreled many type 93 action guns to 7.62 in the 50’s? The 7X57 has a pressure of 46,000 lbs cup. The 1893 action is designed within these parameters. However, all actions are “proofed” with a high-pressure cartridge, often called a “Blue Pill”. That proof cartridge is far in excess of the 7X57’s pressure of 46,000 lbs. All Mauser actions have a fair bit of insurance built into them, they have to. However, they are not meant to push the envelope all the time with high-pressure rounds. Is the 7.62 NATO excessive for a type 93 action? No it’s not.
What is the pressure of the 7.62 NATO? Cartridges of the World, 5th Edition by Frank C. Barnes, DBI books, 1985, state the 7.62 NATO, M80 Ball, the standard rifle cartridge, has an average max pressure of 50,000 psi. The 50,000-psi of the 7.62 NATO is within the safety factor of a proper functioning type 93 action.
The Spanish FR-8, originally a 8X57 short rifle with a 98 type action, rebarreled in the 1950’s to 7.62 NATO
As we said before, military rifles tend to have roomy chambers, usually crowding the high side of tolerance. Throats also tend to be on the long side. Both these factors translate into slightly reduced pressures. This brings the 7.62 NATO’s 50,000 psi much closer to the 7X57’s 46,000 psi. So, it seems that firing the 7.62 NATO round in an 1893 type (in good condition), that has been rebarreled and marked 7.62 NATO is safe.
No less of an authority then Frank de Haas, in his book Bolt Action Rifles 4th Expanded Edition, Krause Publications, 2003, states this about 1893 type actions: “I advise limiting the cartridge choice to those originally used, or to other cartridges within the following limits: any cartridge developing less then 45,000 psi breech pressure…I consider all of these actions…as having marginal strength and safety for the .308 Winchester (7.62 NATO) cartridge.”
Notice de Hass states “marginal”, not dangerous. Again, this seems an admonition to proceed with caution, not a condemnation of the 1893 type.
After WWII, Parker O. Ackley preformed “blow up tests” on military actions. In his book, Handbook for Shooters & Reloaders, Volume II, Plaza Publishing, 1966 he states: “It was found the Mauser actions to have a low carbon steel, and were heat treated by a carburizing process. This process is known to the layman as case hardening.”
The Mausers have a softer core to withstand the effects of impact, and case hardening on the outer surfaces to resist wear. Ackley had to put excessive overloads in the 1898 type to blow it up. However he did find excessive headspace began to develop before the action blew up. Ackley did not do a test on the 1893 type action, however, his comments about the way Mauser actions were built also applies to the 1893 types.
