Manufactured from 1861 to 1862, this is an improvement over Allen & Wheelock's sidehammer revolvers. It is believed that a very small group of this type of revolver was issued to the 2nd and 3rd regiments of Michigan cavalry during the Civil War and 536 revolvers were bought by the U.S. government in 1861. The left barrel flat is stamped with the two line address/patent dates (1857, 1858) marking. Matching number "209" marked on the left of the grip frame, underneath both grip panels, rear face of cylinder, and underneath the trigger guard/ramming lever.