[geladen]

It would be a Gewehr 98 bolt that had been inspected, accepted, and so marked -- but not marked as having been proof fired. Possibly from 'work in progress' at the end of WWI.

 

[geladen]

The inspection/acceptance mark is the crown/c; there is also crown/a, etc. The firing proof was marked on the receiver, barrel, and bolt.

See: http://forums.gunboards.com/showthread.php?855-Gew98-Research

A good reference book is Mauser Military Rifle Markings, 2nd Edition, 0967689635.