Downloading modern CAD files from a shady "Rapidshare" alternative (like unknown torrent trackers) exposes you to malware. Blueprint files are often disguised .exe files or password-locked .rar files that contain keyloggers.
The Deutsches Waffenmuseum (German Weapons Museum) in Oberndorf has digitized some original Mauser factory drawings. While you cannot download them via Rapidshare, you can purchase high-resolution TIFF scans for a nominal fee (€10-€30 per sheet). This is the gold standard for restoration. Mauser K98 Blueprints Rapidshare