Quite a gun, both of them. I must have missed most of this the first time through, as I remember you discussing how you did the silver additions to the brass, but the finished gun is new to me.
I have to ask, do you know why the catch internals protrude through the buttplate? Unless it is just a matter of space the only purpose I can think of is that it gives a way to tap the catch shut if it gets stuck open, which seems a rather unlikely situation.