The K100 is a 9×19mm semi-automatic pistol designed and built by Grand Power s.r.o. in Slovenská Ľupča, Slovakia located approximately 11 kilometers east of Banská Bystrica, Slovakia which is the region's major city. Development The K100 was developed by Jaroslav Kuracina, a former weapons officer in the Slovak Army. Kuracina sketched drawings of the K100 as early as 1992, but manufacturing activities were highly restricted during the early post-Communist era. Kuracina would be forced to wait until 1996 to continue development of his design. In 2007 Grand Power announced a deal to produce 100,000 units for the U.S. market in partnership with Texas-based handgun manufacturer STI International Inc. The first pistols were exported in 2008. They were K100 Mk6 pistols under the commercial name GP 6. Design details The K100 uses a rare rotating barrel locking system, similar in some ways to the Beretta Cougar, Beretta Px4 Storm, and Brügger & Thomet MP9, which in the K100's case is cammed by a cross pin. When the pistol is fired, the barrel and slide move backward together for about 3/8 of an inch while the barrel is cammed clockwise (with respect to the shooter) by a flat, twisting, helical "cut" in the barrel extension. Once the barrel and slide have moved back to the point where the barrel has twisted about 45°, the slide is free to continue traveling back while the barrel's travel is arrested by its interface to the frame via the barrel extension's square shoulders. On the K100, the Beretta's barrel extension cam cut, and transfer block's cam tooth, are replaced by a curled, twisting cut in the barrel extension, and a round, frame-embedded cross-pin respectively. As such, there is no transfer block (locking block) per se, and the barrel extension directly interfaces with the frame via the replaceable cross-pin. The design allows a low bore axis relative to the shooter's hand and avoids the use of the transfer/locking block typically found in rotating barrel pistols. Both of the Berettas, and the K100, have the archetypal square shouldered lock protruding from the otherwise round barrel, easily visible at the ejection port with the slide fully forward. This square shoulder is rotated in behind a solid column of steel running the length of the slide forward of the ejection port, and on the left side out of view, when the slide and barrel are fully forward in battery. This