Offered here is an extremely rare and significant piece of Colt history; the only opportunity Rock Island Auction Company has ever had to be able to offer a genuine Colt experimental prototype Model 1851 Navy revolver with a 6 1/2 inch round barrel, bearing serial number 167907, as manufactured in 1863 during the middle of the Civil War. This specimen comes with a very strong pedigree, as it was formerly a part of the Colt factory museum collection housed at the Connecticut State Library. It was also recently on loan and displayed for the last 6 years, showcased in a floor table display at the NRA Gun Museum inside Bass Pro Shops of Springfield, Missouri. This exact revolver is pictured twice in "The Book of Colt Firearms" by Sutherland and R. L. Wilson, on pages 120 and 129, with the latter caption stating, "Serial #167907. Model 1851 Navy, originally in the Colt Factory Museum collection. 6 1/2" round barrel. The serial number ranges of this rare variation were #167900, #174000 and #186000. A specimen with relief carved select walnut grips, serial #174064, is in the Connecticut State Library collection. Only part of the U.S. America barrel marking is visible. German silver blade front sight; varnished walnut grips." This exact revolver is also pictured on page 113 in the recent 2024 publication of the "Fine & Historic Arms Annual" sponsored by the Texas Gun Collectors Association and Rock Island Auction Company. The Colt Model 1851 Navy or "Revolving Belt Pistol of Naval Caliber" was the second most popular of all Colt percussion revolvers after only the more compact Model 1849 Pocket. When Samuel Colt was alive, it was this model that was probably the first to come to mind when someone brought up Colt's innovative "revolving pistols." Many were presented to influential individuals at home and abroad to help establish the quality of Colt's wares. It was an excellent revolver for lawmen, soldiers, and every day citizens who might need some protection. It had more power than the 1849 Pocket but was still much easier to carry than the massive .44 caliber Colts such as the Walkers and Dragoons. Standard Colt Model 1851 Navy revolvers typically have a 7 1/2 inch octagon barrel, whereas this experimental revolver has a 6 1/2 inch round barrel, likely in an attempt to make a more wieldy revolver that has the ability to smoothly slide in and out of a holster. The top of the original factory round barrel has only part of the last word visible in the one-line "-ADDRESS COL. SAML COLT NEW-YORK U.S. AMERICA.-" address. A student of Colt firearms can gather that this barrel likely started as an octagon barrel blank that was factory made into a round barrel, and is factory fitted with a German silver blade front sight of the kind typically seen on Colt Dragoon and 1860 Army revolvers. The left of the frame has the "COLTS/PATENT" marking, the cylinder features the iconic Naval Battle of Campeche roll scene, and matching full or partial serial numbers appear on the barrel, frame, trigger guard, butt, wedge, cylinder, and cylinder pin, with an unnumbered loading lever. The factory serial numbers on this revolver are in two different size and style stamps. The barrel and cylinder are stamped with a smaller font while the frame, trigger guard, and backstrap are stamped with a slightly larger font. Provenance: The Colt Factory Museum Collection; The Robert Q. Sutherland Collection; The Robert E. Peterson Collection; The NRA National Sporting Arms Museum; The DBJ Collection