there is a little detail, i dont know if it is meaningful or not.
according to görtz (die pistole 08) the bolts of military parabellums were adapted with the grooving about 1930.
he mentioned, that pistols without grooving on the bolt were possibly already in privat hands at this time.
can you gentleman agree with him in this point, maybe this will be a clue for this discussion.
the shown 1910 has no grooving at the bolt, so possibly already private ....
regarsd, wolfganggo .....