Underhammer Pinfire Pistol by Joseph-Célestin Dumonthier
This is a really early underhammer pinfire pistol made in 1849 by the French gunsmith, Joseph-Célestin Dumonthier who lived in Houdan, Seine-et-Oise, France. It follows his 2 July 1849 French patent.
The whole barrel unscrews from the frame and allows you to load a single 12mm pinfire cartridge.
This pistol was made before the pinfire cartridge sizes were more standardized and it will actually not accept a normal 12mm pinfire cartridge which is slightly too large. It uses the earliest style pinfire pistol cartridges such as these made by Jules Joseph Chaudun.
Dumonthier would later become better known for making unique pinfire guns such sword pistols.
The French patent that this gun follows was deposited on 2 July 1849 and was issued on 4 September 1849. It was given number 8523 and the full specification and drawings can be seen below.