As Raimey called upon us: I have not enough information to even start looking for an educated guess. All I know now, it is on a Drilling retailed by Miller & Greiss in Munich, but most likely made for them by the Suhl or Zella-Mehlis guntrade. What type of Drilling? Calibers? Where and when was it proofed? All this info is needed to narrow down the area and time span. Without photos of the gun's action area and of the proof- and other markings I will not even speculate about that stamp, as doing so is wild guessing only. I have learned this from experience by answering many such questions. Just a few days ago, someone asked about dating a rifle. As he referred to Jon Speed's Mauser books, I automatically assumed it to be a bolt-action rifle. As it turned out, it was a Suhl-made double rifle, proofed April 1937, according to the date stamp of the proofmarks. Or, another "German trademark" turned out to be on a Belgian gun only retailed by a German country gunshop.