The M1901 Mannlicher Self-Loading, Semi-Automatic Pistol was an early semi-automatic pistol design. General features This pistol is one of the most simple of blow-back semi-automatic pistols ever designed. The lockwork is essentially that of an elementary single action revolver. While technically listed as a 'hesitation' lock because of a delaying cam which has some theoretical tendency to slow down the opening of the breech, in actual practice it functions as an unlocked pistol. According to the Steyr factory records this arm, patented in 1898, was originally introduced as the "Model 1900" and used a special 8 mm cartridge. When introduced commercially in 1901 it was chambered for a special straight-case cartridge listed in Austria as "7.63 mm Mannlicher", designated in Germany as "7.65mm Mannlicher" (Note: There is also another 7.65 mm Mannlincher cartridge, M.1903, similar to 7.65 mm Borchardt), and described in the U.S. as "7.65 x 21 mm". The Mannlicher "straight sided" cartridge actually has a straight taper to help in extraction. The cartridge for this pistol was manufactured in Europe until the beginning of WWII. The cartridge has a bullet weighing approx. 85 grains (5.5 g) which may be steel or cupro-nickel jacketed. The powder charge varies with the type of powder used, the European standard being about 3.5 grains (227 mg) of DWM standard powder, producing a muzzle velocity in the neighborhood of 1070 ft/s (326 m/s). While this is a cartridge of considerable power to use in a blow-back action, the pistol design itself is so sturdy that it tends to be very reliable through the years. The firing chamber in this design is part of the receiver proper. The fixed magazine is housed in the grip, and is loaded with a stripper clip through the top of the open action. Because of the extremely simple lock work employed, the pistol has a minimum bulk for an arm of its type. Breechblock design The moving breechblock of this pistol was designed as a slide with two rails extending forward beneath the stationary receiver/barrel where they are connected by a cross beam which is also part of the single breechblock forging. The barrel is screwed into the chamber section of the receiver and has a front sight top rib which is part of the barrel forging. A spiral recoil spring is positioned horizontally, directly below the barrel between the parallel guides of the receiver and rails of