The easiest way to put an optic on your old German warhorse is this AIM Sports upgrade set for 98K rifles. The lightweight aluminum mount's drop-in design provides 5.25" of rail space and installation requires no drilling, tapping, or gunsmithing. This set from AIM includes a long eye relief scope, scout scope mount, and rings. Just add your Mauser.
Features and Specifications:
Manufacturer Number: CKK98
Color: Black Anodized
Weight: 2.7 oz.
Accepts all standard Weaver/Picatinny 1913 accessories
Most Mauser Karabiner 98k rifles