The Obregón is a Mexican designed semi-automatic pistol designed in the mid-1930s by a mechanical engineer, Alejandro Obregón. It uses the same .45 caliber ammunition as the Colt 1911 and resembles it in overall appearance, frame size and weight. However, its short-recoil operating and barrel locking system employs a diagonal cam on the rear of the barrel sliding against a diagonal receiver-mounted groove to rotate the barrel, much like that of the Austro-Hungarian Steyr M1912 pistol, not the "swinging link and pin" of the Colt M1911 series.
One of the Obregón's design curiosities is that its safety switch and slide lock are a single unit. A few hundred of these pistols were produced at the national armory in Mexico City during the 1930s, but it was neither a sales success nor was it commissioned to be made for the Mexican government.