Manufactured in 1876. London proofs are behind each of the cylinder flutes and on the bottom of the barrel at the breech. The top of the barrel has the one-line Hartford address, the left side of the frame has the two-line patent dates marking, and the left side of the trigger guard is marked "45 CAL/B." Matching serial numbers are found on the frame, trigger guard, back strap, cylinder and barrel. The revolver is plated in nickel, a highly desirable and uncommon finish found on early production Colt Single Action Army Revolvers. According to Colt historian and author R.L. Wilson, Colt manufactured only 729 standard Single Action Army Revolvers chambered in .450 Boxer for sale throughout the British Empire. Early production Single Action Army Revolvers with British proofmarks are scarce.

Very fine, retaining 70% plus original nickel plating with flaking and mottled gray patina on the balance. The grip is very fine with high edge wear and some minor-moderate handling marks. Most of the original varnish remains. Mechanically excellent.