Others more knowledgable on here will be along to help you shortly. I do not think it is a Pin fire, but a needle gun. Pinfire typically had hammers to drop onto a pin projecting from the side of the cartridge, above the barrels. I am not well versed in these but would think it more likely to be from about 1850 -1870 after which cartridges as we currently know them replaced earlier ignition systems quickly. There will be some proof marks on it if made in either France or Belgium to identify the source country and perhaps more info on date of manufacture. I think they are fairly rare because the technology was awkward and fragile, competed with sturdy percussion systems and dissappeared quickly with the advent of brass cartridges in a very short period. The majority of them were military arms I believe while this is a sporting arm.
