[Popgunner]

You would be safe to buy a rifle marked for .308 Winchester & fire 7.62 NATO ammo in it. 7.62x51 NATO ammo has a max pressure of 49,700 psi (usually called at 50,000 psi). SAMMI max pressure for the 308 Winchester was for years listed at 52,000 psi. Then that pressure max was raised to 62,000 psi.

One thing to remember is that rifles such as the Spanish Guardia Civil 1916 rifles were tested at NATO pressures & approved for the NATO cartridge-not the CETME pressure which is even lower. I have one of these 1916 rifles & it's been reported that firing lots of .308 win ammo in them will eventually bend the bolt locking lugs enough to stop the gun from firing. I load light loads only for it.

Another thing to remember is that 7.62 NATO cases are(edit:can be) THINNER than commercial brass-the opposite of the norm of military brass being thicker than commercial brass. Loads using NATO brass at max .308 Win levels should be reduced by at least 2 grains.

I have recently bought a Savage rifle in .308 Win that I've shot NATO ammo in & gotten very good groups with it.