The Steyr GB is a double-action 9×19mm Parabellum caliber, large-framed semi-automatic pistol employing a gas-delayed blowback action. As such the GB abbreviation stands for Gasbremse (gas brake). It was designed in 1968, intended as a replacement for older handguns in Austrian military service. The weapon went into general civilian production in 1982, and in 1988 production ceased. In the late 1970s, an American company founded by Les Rogak, LES Incorporated of Morton Grove, Illinois marketed the Rogak P-18, a close derivative of the Austrian original, but without great commercial success, due to significantly lower manufacturing standards which affected both the appearance and function of the pistol. Both weapons are now regarded as collector's items, the original (Steyr) model commanding higher prices in the American market. Operating mechanism The Steyr GB is a semi-automatic, blowback-operated firearm. It features a unique gas-delayed blowback system based on the Barnitzke system, first used in the Volkssturmgewehr 1-5, and subsequently in the Swiss Pistole 47 W+F (Waffenfabrik Bern) prototype pistol. The Barnitzke system uses gas pressure from the ignited cartridge and feeds it through a small port in the barrel in front of the chamber to retard the rearward motion of the slide. This is accomplished by using the fixed piston formed by the outside of the barrel inside a moving cylinder formed by the inside of the slide and gas pressure in the space between them opposing the rearward motion of the slide until the gas pressure has declined (at which point the bullet has left the muzzle) thereby allowing the slide to continue its rearward motion. Thereafter the Steyr GB follows the conventional semi-automatic cycle: opening the breech; ejecting the empty cartridge case; stripping a new round from the magazine; loading a new cartridge; returning to battery (unless the magazine is empty). Development History of GB At the end of the 1960s, Steyr-Daimler-Puch in Austria started re-examining the Barnitzke locking system and started a follow-up development. This led directly to the development of what would eventually become Steyr GB. The final patent specification from December 6, 1972 by the Steyr designer Hannes Kepplinger is based on the Barnitzke system, although this was significantly improved in terms of design. The GB was designed as a full-size military sidearm with the goal of replacing the ageing Walther P38 and Colt P11 from the army stocks, as well as the Belgian FN M35 used by Austrian