DRP = Deutsches Reichspatent = German patent
DRGM = Deutsches Reichsgebrauchsmuster = protected design
Inscription found on all Mauser B smallbores.
The Gerard, Berlin "Landlicht scope is contemporary. Such small 22mm scopes by various makers were originally mounted on customer's request. But the icing on the cake are the rare original Mauser factory scope mounts, see John Speed's book:"Mauser Smallbores", page 95. (The rest of the book may be of interest too) Usually these rifles are found with contemporary scopes and contemporary aftermarket mounts, mostly lever-type ones by AKAH.