Found in a World War Two veterans estate, WWII bring back.Vintage miniature cap gun on a keychain. I assume keychain was a later add on and not original to the gun.DRGM or Deutsches Reichsgebraichsmuster marked on the side plate.This mark indicates a German patented product made between 1891 to 1949.Brass barrel appears to be 2mm and is 1 3/8 inches in length.Good working condition, hammer cocks and trigger works.See the photos.