[mrerick]

The area that Ed circled in his post is the main reason I posted these comparison photos.

There is considerable variation in this area. It looks like the different manufacturers used a different diameter milling tool, but also that the technicians doing the milling added variability in this area. It's possibly a unique signature for an individual Luger.

The shape and position of the rest of the front edge of the ear is critical to the timing and operation of the Luger. Even very subtle changes to this profile (as highlighted by Vlim) will change this timing.

There are also subtle differences to the inside profile thickness along the inside edge of the front of the ears. These don't affect operation, but also provide a shape signature.

I don't have any Krieghoff Lugers to post, but I do have the Gibson book and will check it out...

Marc