This is an extremely rare example of a Mauser Model H prototype semi-automatic pistol chambered in 9mm Luger (Parabellum), dated 1917. It appears to possibly be the design of Mauser's brilliant engineer Josef Nickl who developed a series of prototype pistols while working at Mauser, and was also the inventor of the Mauser Model 1910, 1914 and 1934 pistols in 7.65mm auto/.32 ACP. This Mauser prototype pistol, chambered in 9mm Luger, appears to be one of a series of his attempts to scale up the aforementioned smaller Mauser pistol designs and shares many visual similarities with them, as well as the vz. 22, vz. 24 and vz. 27 pistols subsequently manufactured in Czechoslovakia that are also of Josef Nickl's design. It features a barrel assembly that rotates slightly for unlocking, with a hammer and left side mounted safety/slide locking mechanism, and a removable takedown piece on the bottom of the frame that easily allows for removal of the slide assembly. Mauser's German patent number 300159, dated August 31, 1915, depicts a striker-fired pistol with a similar rotating barrel, although this 1917 dated example is hammer operated and also differs in that it has a left side slide lock/safety mechanism and a different takedown mechanism. "Waffenfabrik Mauser A.G. Oberndorf a.N. Mod. H. 1917" marked on the left of the slide, with serial number "10" on the rear of the frame and on various components, with "10" and "1945" handwritten in black ink on the right side interior of the one-piece checkered wraparound walnut grip.

Fine, retains 60% original blue finish with smooth brown patina on the balance, scattered noticeable patches of moderate pitting on the right side of the slide, and distinct slide markings. Grip is very fine with a few dark spots on the rear, some scattered light handling marks, and mostly crisp checkering. Mechanically excellent. An extremely rare and significant evolutionary Mauser prototype Model H pistol worthy of the most advanced pistol collections!