Boxlock double rifle, or Doppelbuchse and possibly a Blitz or triggerplate action? Any image of the floorplate or underside of the action where the horn triggerbow guard is missing?

On the PM I provided the following for terms/definitions & info on the Z-M proofhouse:

http://www.hallowellco.com/abbrevia.htm

http://www.beschussanstalt.zella-mehlis.de/en/

Kind Regards,

Raimey
rse