Well now its mine, but im kind of a modern-technology-guy and i dont really trust an action that is 75 years old. +he never changed a single part, so its ww2 technology all over...
Im not sure if i should shoot it or just hang it on the wall as a family heirloom. Would it be safe to shoot it? Would i have to use reduced loads? I dont want this thing to blow up in my face because the steel of the chamber is to old...
Reduced loads wouldn't be necessary, if it's still 8x57mm Mauser.
It should have a .323" bore, but you'd have to slug it or have a gunsmith slug it (maybe even take a chamber cast), to be sure.
If you wanted to take it easy... All of the commercial ammunition put out by the big American ammo companies is watered-down, to begin with; and most of it has under-sized bullets, in case some one fires it in the older .318" bore. (the bullets in ".323"-marked ammo range from .319" to .321", and are loaded to around 28k to 36k psi, in my experience)
As for the "WWII technology"....
I don't own a rifle that is really any kind of technological improvement over that Mauser. In fact, most of the bolt actions are just simplified versions of the Mauser action... built with the same materials and processes.
My lever action, break action, and pump action rifles are even older technology... some of their basic designs pre-dating that Mauser by 60 years. The only "improvements" to the designs, since then, were cost-cutting changes that simplified the casting/milling/machining processes.
The only thing that really matters, is the way the receiver was hardened. And, in that case, the Germans knew what they were doing.
As long as the rifle is in good condition, I wouldn't worry about it, at all.