This is only the third of these I have personally seen in over 35+ years and is #499 of a total production of only 500. This very unusual revolver was only produced from 1861-1862 and has a 6” barrel. The markings are visible but a bit weak.
This is a very nice example of a scarce secondary US martial percussion revolver (Flayderman’s 5A-061). The “Center Hammer” series of percussion revolvers (including the .44 Army, the .36 Navy and the “Providence Police”), were manufactured during the early days of the American Civil War, after Allen was forced to stop producing their Center Hammer Lipfire revolvers due to their infringement on the Smith & Wesson / Rollin White “bored through cylinder” patent.