I have reservations that anyone but Sauer or their sub performed the tap, tap, tap on the locks. DRGM 17913 around clockhand indicators. I seem to recall that protection was filed for in the early 1890s?
Disk set strikers? Also Z mechanic was more than likely the System fella/action guy.
Selbstspanner - System J.P Sauer & Sohn
Papp. 16-65, 4,75 S.P.(Dram Eq. Powder), 28,5 grammes lead shot
Nicht Für Kugel w/ Latin I(surmounted by a dot)
Multiple Sauer Wildmann & Club process or quality mark stamps.
Images from another thread.
Cheers,
Raimey
rse