Pieper Nicolas mod C
As you had surely guessed it is about a rare gun Nicolas Pieper model C (not Piper: it is reserved for champagne…) gauge 6,35 Browning.
The only iconographic source: the N.Pieper catalogue… and without absolute certainty. Only the right side is presented, and thus not that of the lever of disassembling.
However, in the N.Pieper catalogue, the model C is, all things considered, rather similar to A and the B… from which the lever of disassembling is very different from that of your gun. There would it have had alternatives???
Personally, before your sending only N.Pieper mod.C which I saw (in photograph!) appeared in an article of our friend Dirk Ziesing, published in the DWJ. I think that it is identical to this one.
I confirm his scarcity and his value, being given the remarkable state of conservation of the specimen of which you communicated the photographs to me.
MdS