Doubt very much they would take that pressure as they are a small ring model 1993 Mauser made for the 7x57. Some shoot 308s and say no harm but I would shoot them with reloads that are not max loads if it was me. Here is an article from Surplus Rifle you can read:
Using the model 1893 rifles, Spain developed the Spanish Civil Guard, M1916 Short Rifle, a rifle that changed a 29 inch long barrel to 21 inches. According to sources, these rifles were made by the Ovideo arsenal between 1916 and 1951. Original 1916 short rifles were in 7mm Mauser (7x57). The Guardia Civil rifles, marked with the crest of crossed sword and fasces, apparently were converted to 7.62 from both 1916 and 1893 rifles in the 1960’s. The converted rifles typically have the caliber 7.62 marked on them. The two rifles are very similar except for caliber and barrel length (the 7mm barrel is a hair longer). These rifles are considered to be small ring Mauser receivers and are two-lug designed bolts, lacking the third safety lug commonly found on other Mauser rifles.
This short rifle features a turned-down bolt, recessed 5 round magazine, Guardia Civil Crest on the receiver (as shown below), fixed side support and sling swivel. Barrel length is 21 inches and overall length is 41.3 inches. The sights are inverted-V front and adjustable V-notch rear.
As with any military surplus, the rifle should be thoroughly safety checked. Double check caliber markings on weapons. Both 7x57 Mauser ammo and 7.62 NATO ammunition is available through numerous sources. Note that the 7.62 NATO cartridge is not the same as .308 Winchester commercial cartridge in terms of pressure ratings. Many shooters report using commercial .308 ammo with no ill effects, however REALLY, the weapons are marked for 7.62 ammo with max pressures of 49,700 psi CUP vs. 52,000 psi CUP.
Handloading for the converted rifles is very common to keep pressures/recoil/muzzle blast down. Recoil using the 7.62 NATO ammo is quite stout and some recoil protection is warranted.
Note: These rifles are handily converted to 7.62x39mm using barrel inserts that tame the recoil quite effectively