This is an outstanding example of an extremely rare Walther Prototype Model MP/semi-automatic pistol which features the "exposed" serrated hammer. This model was a continuation of the earlier MP and later MP/PP series of Walther pistols that ultimately lead to the final variation of the standard P-38 pistol. This example is actually like a transitional model in that you can start to see the actual P-38 configuration start to take place in that it has the flat sides on the slide, with the arched slide bridge over the barrel, the two separate takedown and slide release levers, the flat machined firing pin cover the short rear frame area not machined for any kind of a shoulder stock and new exposed hammer. Although it has an external hammer this is an early design in that it has the large serrated round hammer that was adopted from the Model MP/PP designs with the early "anvil" type face on the hammer which was dropped in the HP series. The frame also now shows a slightly straighter grip angle. In 1937 the German patent 726,501 pictures this model MP/H design which was granted in 1938. The serial numbers of this design were also of the "zero" prefix as these were a continuation from the earlier "zero series" MP models. It is estimated that not more than a few (with the exposed hammer) were actually produced as they already had testing/design data from the internal hammer series pistols. So it is theorized that this model was only produced to show the manufacturing feasibility of an exposed hammer. There are only "2" know examples of this model: serial numbers 015 and 017 so it is assumed that they proceeded to produce the new "HP" series. The right side of the frame is serial numbered "015" and so is the barrel lug. The slide is unnumbered and the locking block is numbered "41" on the front face. This model still has the all machined frame with an all machined magazine marked on the lower left side with "015-29". It has the early style fixed, and squared off front sight with the early style non-dovetailed rear sight. The left side of the slide is now marked with the standard two line Walther markings of: "WALTHER" inside a banner followed by "Waffenfabik Walther Zella-Mehlis (Thur) / "Walther's Patent Cal 9 m/m Mod MP". This wonderful pistol is fitted with a set of two piece wrap around, checkered walnut grips with full length checkering on the sides of each grip panel. This is an exciting, all original early Walther prototype pistol. There is limited factory information on these early Walther prototype pistols for obvious reasons, however there are two excellent reference books that provide historical information on this model. They are: Walther Vol. III, 1908-1980, by Rankin, pg. 72-73, the second is "The P38 Pistol" by Buxton, Vol I, pg. 31-33, and pg. 48-67, with this actual pistol shown on page 64.