All in all, Spanish Mausers are not bad rifles, but they are old and worn out, and typically were not very good to begin with. That said, I have owned several of them over the years, and I fired thousands of military surplus 7X57 ammo through them with no issues. When it was time to retire them, they got turned into something I could give away and not feel too bad about it, or they got scrapped.
Lately several of these rifles have been offered to me, and all had similar stories: it was dad's/grampa's/uncle's rifle and now it's mine, what can I do with it. If it's in good shape, it's a shooter. If the rifle is worn out, it's not worth fixing, so let it die.