The first gun with all the details
Piet’s pins arrived today already, and they look so much better. Below is the first attempt. I do not think I will do all of them this way, because I do need to make that deadline of my 50th birthday (only four years to go). So only the visible ones.

I used the ugly pins from the kit to simulate the bolts that join the upper and lower parts of the carriage. The division between the upper and lower part I simply scored with a knife. The handle for the wedge at the back I turned from a piece of scrap wood I still had; that was quite a fiddly job. Hans Groenenberg corrected me straight away: it is the handle of the quoin. The little things on the trucks that stop them rolling off when the gun moves are also made from the kit pins, first flattened, then carefully stuck on with a tiny drop of glue.
The ring for the breeching rope I made from 0.7 mm wire, bent round a pair of round-nose pliers. That is a lot of work and I would rather buy them somewhere. Peter de Vries had a better way: wind wire around a drill bit and then cut through. That way you can easily make every conceivable size in large numbers. Emphatically wind by hand, do not let it spin. I had read something about a drill bit, but did not understand how. How easy can it be.
The compliments on the forum are extra motivation to do more of them this way. I noticed, by the way, that I had still forgotten the breeching ring on this one. And the George cipher is yet to go on.