Re: My first old gun.....Spanish Mauser Info Needed
If the rifles were converted from 7mm to .308 by using a new barrel or by reboring and re-rifling and setting the barrel back, things should be OK. But some of those conversions were done by drilling out the whole chamber area then installing a sleeve chambered for .308. That works, but I am "agin" it on general principles since there is a gap between the front of the sleeve and the front of the bored out area. Gas can get into that area and the result is not too good.
That was done on Chilean Mausers, I am not sure if it was done with Spanish Mausers as well. (See picture of sectioned barrel.)