Williamson Single Shot Deringer in caliber .41 rimfire with auxiliary/adapter percussion chamber. According to Flayderman's Guide to Antique American Firearms, this was invented by David Williamson of New York City and manufactured by Moore's Patent Firearms Company of Brooklyn, New York and later by its successor, The National Firearms Company, also of Brooklyn.
The design shows a clear likeness to Henry Deringer's original percussion single shot pistol from the 1840's...especially in size, profile, and single piece stock. It even uses Deringer's distinctive wrap-around checkering on the grip handle. Internally though, the gun is a completely different animal mechanically speaking. Williamson's design is a true breech loading cartridge gun...but he does a fantastic job of hiding the technology inside the traditional shell of the Deringer tradition. Instead, everything is internally mounted by incorporating an internally mounted one piece brass frame inside the traditional style handle and obviating the external hammer and lockplate mechanism. Instead of the wood being the central mounting point for various components, the frame that houses a centrally mounted hammer, mainspring, firing mechanism, locking mechanism for the barrel and the barrel itself. The barrel design is about forty years ahead of its time...it's fashioned like the slide on a semi-automatic pistol...the frame acting as a bed with mortised grooves to allow the barrel to function as a sled back and forth to gain access to the breech. This is pretty incredible stuff for the 1860's. It makes one wonder if early designers of the automatic pistol like John Browning had a chance to study this design thirty years later. Williamson hid this fantastic design by mounting it into the Deringer profiled wooden stock...quite an understatement for such a well thought out frame. Instead, Williamson must have been content to stay within the traditional dimensions and aesthetics of Henry Deringer's famous and oft-copied design. Williamson even found a way to fire the gun in percussion mode...another smart move that must have eased the worries of customers, many of whom were probably purchasing their first cartridge gun back in the 1860's. Provided with each gun was an auxiliary chamber...a steel cup with a percussion nipple centrally mounted...which acted in similar fashion to a central fire primer found in cartridges today. To achieve this, there are two points of ignition...one through a rimfire firing pin located on the top of the hammer, the other through a small hole in the back of the frame where the body of hammer would make contact with the percussion cap. Unfortunately, this innovative design was only manufactured for approximately four years (1866-70) when Colt Patent Firearms bought out National and dissolved the company. The only National product to survive was the No. 2 Single Shot Deringer which was added to the Colt product line...also in .41 caliber.
Overall condition is NRA Antique Very Good. The metal is in great shape...the barrel showing only original finish in external areas with sharp edges and clear markings. This includes two fantastic engraved arrows running down each side of the barrel...a distinctive feature found on many surviving examples of Williamson Deringers. Williamson's Oct. 2, 1866 patent date is located on the top flat of the barrel. The brass frame has aged to a perfect and even patina with original silver plating in internal areas. Barrel is numbered to the frame. The walnut grip is in Fine condition with no damage and fairly minimal handling wear. The original wraparound checkering is still sharp and has never been re-cut. The mechanics are in very nice shape. The auxiliary chamber is still with the gun. It's very old, its condition consistent with that of the gun itself and appears to be original. The bore is Excellent...bright and shiny with strong three groove rifling. This fantastic little pistol comes to us from an old collection. These are seldom found with the auxiliary percussion chamber! An impressive gun in both design and condition.