Thank you so much about reply.
I wonder, if it's possible to find out the exact year of made by the serial number, since the serial number is 18739? Does the serial number indicate year?
"BP", "BV", "NP" proofs started in 1904 and by the IGC, Altendorf & Wright closed in 1915. It means that gun belongs to the time between 1904 and 1915, but I still don't know the exact year.
Franc, what do you mean by "what kind of 3rd bite is that on the rib extension???"? You mean bite on the rib extension at the beginning of the barrel or something else? If it's that, the bite is part of the locking system.
I'm posting 2 more pictures that show maybe some more details of the sides that are not visible at the previous ones.
Emilio