Mikey
Lots of misinformation out there on the so called pressure difference between 7.62 NATO and >308 Winchester. Most comes from comparing different methods of obtaining "psi", comparing psi to CUP and comparing average working pressures to maximum allowable pressure. Let me quote from TM 9-1305-200 dated June of '61 regarding the pressure for M80 Ball; "The average chamber pressure may vary from 45,000 psi to 65,000 psi, depending on the temperature." That TM also relates that average working pressures are held within +/- 7,000 psi. Now considering most quote the SAAMI maximum pressure figure for .308 Winchester as (quotes vary) in the 60,000 psi range and you see there isn't any difference. US 7.62 NATO ammuniton is loaded right up there. Now, referencing this thread regarding the M1916 rifle, the Spanish manuals for that rifle have it used with Nato Spec 7.62 ammo and the 7.62 CETME round may lso be used. Keep in mind that the development of the Mauser actions was one of continual progress and improvement. The M93 was not designed "just" to handle the pressure of the 7x57. It was designed to be as strong as it could be. The Spanish found, as others have that a M93 action still in good condition will handle modern cartridges. These rifles were not made just for the CETME cartridge. BTW; the CETME cartridge was made so the original CETME rifles with unfluted chambers would function.
Larry Gibson