Jeff,
as a collector we do both: collecting and sharing. I learned the guns designation is "Carabina Rayada para Cazadores Modelo 1857/59" (=rifled Jaeger carbine). The 59 is not official, indicating some changes (rear sight, calibre) to the 1857 model. Mine has the known MADRID 1861 marking, indicating that it was made by Riera Zamora y Compania, Madrid (and not by a State arsenal as Firearms fom Europe says). Calibre is neither .58 nor .577 but 14,4mm (was reduced from 14,8). Barrels are from the Trubia factory and bear its marking. Other makers, Ybarra Placencia and Z.V.y Compa. (unknown) exist. Riera made presumably 1000 guns of this type, although the order was between 3-4000 guns.
Would be of interested which markings are present on your guns.
Best,
Marc