In Weapons of War I've profiled a number of different methods of operation for pistols, from locking toggles to Browning actions. The Campo-Giro Model 1913 was simple in how it operated. The slim semi-automatic pistol relied on the rearward forces of the 9x23 Largo caliber to operate it.
Designed by the Count of Campo-Giro, witness to Spanish American War campaigns in Cuba, the pistol started out development in 1900 and went through refinements to eventually become adopted by the Spanish Army.
Well made and simple to operate, the Campo-Giro weighed just over two pounds and fired the Spanish 9mm round at just over 1,100 feet per second. The six inch barrel was encircled by a exceptionally strong recoil spring. When a round was chambered and the hammer dropped, the bullet would leave the barrel while the rearward force of the case moved against the slide mechanism.
Since the slide was not locked to the frame like other pistols, the recoil spring around the barrel physically slowed down the rear movement of the slide. As the slide moved back, the spent case was ejected and a fresh round stripped from the magazine in the grip.
Interestingly, pistols of the time had two releases for the magazine. Either a button just below the the trigger loop or a button at the heel of the grip released the magazine from the pistol. The Campo-Giro however went in a different direction for its magazine release. At the rear of the grip near the slide was a lever, a position traditionally the location of the safety, that released the magazine from the grip.
Later generation of the same pistol moved the magazine release to the left side bottom of the grip plate.
One thousand Model 1913s were made before the change of the mag release. Thereafter 13,000 more Campo-Giro's were made.