The Campo Giro pistol is named for its designer, Lieutenant Colonel Don Venancio Lopez de Ceballos y Aguirre, Count of Campo Giro. The Count was a member of a committee set up to select a self-loading pistol for service with the Spanish Army and set about designing his own. The Army had already specified that the pistol should be chambered for the 9mm Bergmann-Bayard cartridge (which would become know as the 9mm Largo in Spain). Unusually for a pistol chambering a cartridge of this power, the Campo Giro used an unlocked breech with a substantial return spring.
The resulting weapon was adopted for service by the army and produced by the Basque company Esperanza y Unceta in two variants, the Model 1913 and the improved Model 1913-16. The general design concept behind this gun was to influence a whole series of later pistols produced by Unceta.
Stamped on left of frame
Pist.a aut.a mod. 1913-16 over 6440
Stamped on top of slide
CAMPO-GIRO PAT. 34798-54214 1904-1913 over star in wreath trademark over ESPERANZA Y UNCETA GUERNICA