Carl Bock opened his gunshop in Frankfurt on Main in 1897. He died in 1945. Changing addresses were Schaefergasse 44, Berliner Str. 28 and Stiftstr. 21.
This combination was first proofed in Suhl between 1893 and 191I as the bore/land diameter of the rifle barrel is still marked with the old gauge number 129.43. It was Nitro reproofed (I = Instandsetzung = repair) by the Suhl proofhouse (“pick and sole” shield) in 1043 = October 1943. At that time the cartridge designations 9,3/72 and 16/65 (16 2 ½”) were added.
The base for a Greifelt slide-on mount was probably added in the 1920s. The mount top and the Hensoldt Ziel-Dialyt scope from the 1930s don’t really fit the base. See the rear locking lever hanging out in the air behind the base.