Badgerben,
I've seen and examined dozens of the M1916 spanish mausers in both the original 7 x 57mm and the .308 re-barreled calibers. They were all Spanish military arsenal manufactured (marked Oviedo, La Coruna, etc).
LOTS of them have shown excessive headspace from bolt set-back and even from those that were properly gauged with replacement bolts at time of re-barreling. Even in the original chamberings, many of these surplus rifles have seen so much abuse and firing with the hot military loads that they show excessive headspace.
In short, it's probably NOT a good idea to think about shooting one of these in .308 Winchester caliber.