The Roman Number X, or 10, appears to be the assembly number. A quick search may have revealed that my first guess was way off the mark and that the longarm may have been totally manufactured in Saint Etienne. Preynat & Clavier was active in the latter part of the 19th Century from rue de l'Epreuve and may have been producing arms around the 1840s time period. The "AR" seems to fit for Auguste Robert, either an apprentice of Pauly or a student of his work, who ceased circa 1840. He designed a cartridge type rifle for the French military in the early 1830s, but tests found it lacking and he changed horses to hunting type arms only. Sources give Reverend Forsyth credit for discovering fulmiate and the source of the copper cap varies from Joshua Shaw to Francois Prelat but around 1830 it came into use,
http://en.wikipedia.org/wiki/Percussion_cap . So if caps were used in the early 1830s and Auguste Robert folded up shop in 1840, the longarm could have been made in that decade or shortly thereafter. The "S*G" is an interesting mark in that it was stamped twice. 1st possibly in the S*G shop and maybe later by the finisher since it wasn't totally visible. I've read that in order to track who made what in order to get paid that previous stamps were sometimes refreshed. Either the dies were struck differently or different dies were used. I seem to have come up short on the "S*G" mark in that the only firm I could find was Sarda et Gonon and the listed time period was post WWI.
Any matching marks on the frame?
Kind Regards,
Raimey
rse