At 1st glance it looks Belgian, then maybe sourced from the pool of mechanics at Zella-Mehlis. I wonder if it is a true triggerplate(not sidelock) and would really like to see the proofs. I'm curious if it is based on this patent(Societe Anonyme Fabrique Nationale d'Armes de Guerre 15236(British??) for 1906) :

http://books.google.com/books?id=mPZYAAA...gun&f=false

Peter, can you oblige me and pull the image to post it here? The pin configuration seems to match???



Kind Regards,

Raimey
rse