This is an extremely rare, prototype, Mauser large frame, military designed 9 mm pistol. As we know from various examples, the Mauser factory originally designed and developed the small compact, double action HSc model pistol specifically as a pocket pistol in late 1939 with its unique concealed hammer and double action design. However, earlier they were also experimenting with designing and producing a similar "large frame" pistol design that chambered in the military designated "9mm Luger" cartridge. It is believed that this experimental/prototype pistol clearly pre-dated the later Mauser HSc model as this pistol was produced circa 1934/35 given it carries the early commercial "Crown/U" firing proof used by the Mauser factory during the mid 1930s when Mauser was starting to produce military contract Lugers. Obviously, this large frame pistol was intended to be an improved and much simpler to produce design intended to compete for early military contracts against the original German P.08 Luger and later Walther P.38 pistol contracts. In viewing this pistol, you can see by the direct lineage lines of the later HSc pistol as it has the same grip/frame design and angle. The overall slide design is also almost identical other than that it is considerably larger than the HSc. The barrel measures approximately 4 3/4 inch, and it has the square shaped slide with concealed hammer design. This model has a push button magazine release on the left side and comes equipped with a lanyard loop on the lower rear area of the frame, both features clearly intended for military use. The overall takedown mechanism is exactly the same as the later HSc model; however, internally it has a far more complicated and robust dropping link/barrel locking system designed to handle the increased pressures of the 9 mm cartridge versus the simple, blow back design of the small HSc pistol with the 7.65 mm cartridge. The pistol is shown disassembled to exemplify the aforementioned complicated system. The pistol is unmarked except for the "Crown/U" firing proof noted above and the serial number "2" stamped on the spine of the magazine. It is fitted with a set of checkered walnut grips.