Thanks for the detailed description and pictures. I was unfamiliar with this type of action until now.
Jim
That's why i took the pictures its unusual and unless you have owned one or worked on one you will probably never see one in the field or in the gun shops. Its a very basic and simple mechanism but the interactions of all the parts are pretty unique.
A few years back the (London) Proof House would happily give a Proof Exemption on something like this. They have probably got a bit more selective since I was involved.
I had not thought about getting an exemption.. really a re proof would be nice but i doubt 20 thou would go through re proof i know much thinner have passed a re proof but as we know the poof houses are as much destroyers of fine guns as preservers; i would rather this was not blown up.