This model was designed by Samuel Colt and referred to in factory advertisements and labels as "New Model Pistols." Only 14,000 were manufactured in .31 caliber compared to 26,000 in .28 caliber. It is believed that this model was specifically designed to compete with Colt's rivals in European markets, but this model was never as popular as the traditional open top Colt percussion revolvers despite its excellent design. This revolver was manufactured in 1865 and has London proofmarks on the left side of the barrel, on the cylinder, and in the cylinder flutes along with the patent date in one flute of the extra fluted cylinder in the case. The matching serial numbers (second cylinder not numbered) places it within the Model 6 range. Aside from the proofs, it has the standard markings and features. It comes in a hardwood case with English fitted interior, "14, Pall Mall, London, S.W." addressed Colt directions sheet on the inside of the lid with information on loading and caring for "COLT'S NEW MODEL PISTOLS, RIFLES, CARBINES, AND SHOT GUNS," green baize lining, Eley Bros. cap tin marked "Made expressly for/COLT'S PT/Belt and Pocket/PISTOLS.," James Dixon & Sons pocket powder flask, L-shaped combination tool, bullet mold, bore rod, Dixon & Sons oiler, key, and mix of ball and conical bullets.