Valentin Hfner/Haefner Bchsenmachermeister in Kassel hung out his gunmaking shingle in 1804 and I'm fairly confident that a Hfner heir continued the craft and was dubbed by a royal dog catcher/handler in someone's royal court in 1884. So the longarm will date post 1884 with the Knigl. Hofbchsenmacher advertising atop the tube. Circa 1928 he passed the wand to a Carl Spangenberg.
I'd hazard a wild guess the chambering is some 11mm variant but some measurements & a chamber cast will ferret out the demon cartridge. It is a Lefaucheux platform with a sculpted barrel.
Cheers,
Raimey
rse
