Assuming you're asking about the 1916 Spanish Mausers (ex-Guardia Civil rifles), they all started life as 7x57 rifles, then were rebarreled in the 60's.
There is considerable controversy over the wisdom / safety of shooting .308 Win or 7.62x51 NATO in these rifles. An internet search will get you as many rabidly conflicting opinions as you desire. It's your money and your face / eyes.
Personally, I would not shoot .308 Win or 7.62 NATO in these rifles, but I would happily buy one and shoot it a lot.
1) These are basically small ring (1893-type) Mauser rifles lacking the model 1898's extra "safety" lug on the bolt and gas flange on the bolt shroud, so if you do have something bad happen, there's more chance you'll be damaged by it. It's pretty well-established that small ring Mausers are not happy on a steady diet of 50K psi loads.
2) When the Spanish rebarrelled these rifles, they weren't being a bunch of careless risk-taking fools: they intended these rifles to be used with the 7.62 CETME cartridge, NOT the 7.62 NATO. The 7.62 CETME was a short-lived Spanish cartridge that is dimensionally identical to 7.62 NATO, but is loaded much lighter, about like .300 Savage or .30-40 Krag.
Therefore, if you reload, and especially if you shoot cast bullets, these would be wonderful rifles; they are, after all, Mausers. Just give them a diet of light handloads and all will be well. Even the light handloads are plenty powerful for deer-sized game.
If you don't reload, it's a good excuse to start; the rifles are cheap enough to justify the reloading equipment. Just be sure to mark and segregate your 7.62 CETME loads from your 7.62 NATO loads.