This early production U.S. contract Cavalry Model Colt Single Action Army was sub-inspected by Orville W. Ainsworth. The revolver was examined by noted Colt historian and author John Kopec. In his accompanying letter of authentication from 1992 Kopec confirmed the revolver was a first year production example, sub-inspected by Ainsworth, and was likely issued to the 10th Cavalry. The 10th Cavalry was among the first regiments to receive the Cavalry Model revolver, and the first 1,000 were shipped on December 22, 1873 and are found in the 177-1191 serial number range (Lot 1). Kopec noted that the sub-inspector "A" and "P" proof mark "have been worn away" from the cylinder and the hammer is a later production replacement. Ainsworth's "A" is present on the trigger guard, back strap, and barrel but are very faint. A "P" proof mark appears on the underside of the matching number barrel. The top of the barrel has "+COLT'S PT. F.A. MFG. Co. HARTFORD, CT. U.S.A." marking. The left of the frame has the two-line patent dates and "U.S." The assembly number "24" is marked inside the loading gate. Matching serial numbers appear on the frame, trigger guard, back strap, and barrel. The cylinder lacks a visible number. These early Cavalry Models were issued to cavalry units on the frontier, such as the famous 10th Cavalry Regiment (Buffalo Soldiers), and nearly all saw hard use. Surviving examples of early Cavalry Models are difficult to find and inevitably show heavy service wear. Includes Wilson and Sutherland's "The Book of Colt Firearms."