In the "FWIW" category:
The rifle is a La Coruna Modelo 1943, as others have noted. Badly sporterized on top of it all.
In 1943, Spain's military adopted the 8X57IS as its official military cartridge at the advice of German military advisors (who had been advising the Nationalist regime since the 1930s). These rifles were released to surplus in the 1970s after Spain had adopted the NATO cartridges and had switched most of their military and police to more modern weapons. They were in beautiful condition, for the most part.
So no one brought it home from any war, regardless of whatever story went with it.