I would take 6,5x57 brass thats easily available but the common suspects 8x57, 7x64, 30 06 should work

going back to the roots
old sporter making from a M 71 Jaegerbüchse
http://egun.de/market/item.php?id=6844629

its no thread about military rifles but this old Mauser is remarkable
a M 71 rifle that got a liner in 8x57I
http://egun.de/market/item.php?id=6809595

can't remember seeing another M 71 in 8x57 before