The San Cristobal armory was a surprisingly large-scale arms manufacturer set up in the Dominican Republic in the late 40s. They produced several different weapons, but the most common was the Model 2 Cristobal carbine. Designed by Pál Király, it was a lever-delayed blowback mechanism chambered for the US .30 carbine cartridge (7.62x33mm).
Tens of thousands were produced (exact numbers are unclear), and they were a popular weapon in central and south America. Unlike the US M1 Carbine, the Cristobal used a magazine mounted at slightly less than 90 degrees to the barrel. Most of the carbines produced were select-fire, with a front trigger for semiauto fire and a rear trigger for fullauto. A semiauto only variant with a single trigger was apparently also produced. All types are quite uncommon today.
Many thanks to the Royal Armouries for allowing me to film this tremendously rare artifact! The NFC collection there – perhaps the best military small arms collection in Western Europe – is available by appointment to researchers, and anyone can browse the various Armouries collections online.