[SchildaBrit]

Thanks Fernando! It really did not show up yesterday evening, but since then you have given me the "all clear" and I can make progress.

Now I can finally complete the post.

The two photos show a screw taken out of a target rifle by Franz Xaver Zellner, who is well recorded in Stöckel (with several others of his family).
He was an Austrian gunsmith who died in 1768.

So we may deduce that such screws were in use long after the 16th century (as hypothesised in the photo by "matchlock"). That is the problem with technological changes - the forces of "we've always done it like that" are very strong in such specialist areas.

This oddly shaped "hand-carved" screw is (still!) used to hold the back end of the set trigger block in position, the front end being clamped by the trigger guard (a popular method). The bent head enables it to serve as a fixing lug for this purpose. Presumably that was considered to be simpler than making the trigger baseplate longer, with a fixing hole drilled through it and a conventional screw inserted, as would be the modern method.

At present, the rifle is undergoing its 250-year service in my cellar. Like most of my rifles, it's no museum piece, but the bore is great for its age. "Pure" collectors will cringe, but my point of view is that guns are tools, and non-functional tools are of no use to me. And I thus consider it proper to do what anyone of the period would have done to keep them functional.

I would have posted a couple more photos, but they are over the 1Mb limit and I now have to puzzle out how to reduce the resolution so that I can upload them.

And a great New Year to you all from Patrick.