DRGM

AcronymDefinition
DRGMDeutsches Reich Gebrauchsmuster (German: German Reich Registered Design)
References in periodicals archive ?
The "DRGM" was a temporary sort of patent that likely refers to some feature of the gun, possibly the safety behind the triggerguard.
The label is just visible inside the sound hole and the machine head is stamped DRGM 186662.