Blank firing device/Manoverpatronengerät or Platzpatronengerät
The blank firing device is somewhat of a mystery. The original version of the Blank firing device, pictured in the official "D 167/2 Einzelteile" manual was never issued. There seems to be another version of the blank firing device which could be screwed onto the muzzle when the muzzle nut was removed. Around 2005/2006 a lot of these device were offered for sale in Europe. The one that is pictured is actually stamped with a WaA416 Waffenamt stamp. This code refers to two different factories:
1) WaA416 Kimnach & Brunn, Fabrik fűr Heeresausrűstung, Kaiserslautern (code: hjg)
2) WaA416 Deutsche Lederwerkstätten GmbH Pirmasens (code: jln)
But then on the side there is the secret armament code: "dot" which is: Waffenwerke Brűnn, A.G.
This disccrepancy appears to contradict each other! Waffenwerke Brűnn never used the WaA416 stamp. But then I'm not the code expert! Please let me know if you have more information on this.
Since so few blank firing devices with WaA stamp have been made I'm not sure about it's originality. The WaA stamp seems to be slightly bigger than normal original original stampings on parts of similar size. You can compare it to the WaA stamp on the hinged muzzle cap. Since Norway made use of the MP40 after the war it could be that they made use of these devices.