There has to be a German gun specialist near you, if you are in St. Louis. Buck is a Lefever guru and Art is the Belgium gun guy they are both down the street from you. I have heard good things about Mid West gun works but have never used them.
Any body have a ferlach trained guy near St Louis?
Art has restored German box locks for me but that transmission will tick him off.
You may call Buck Hamlin and ask what he thinks or who.