The Colt Model 1877 revolvers were Colt's first double action revolvers and were designed by William Mason who also helped design the Single Action Army. Like the latter, these revolvers were popular in the Old West, and Colt also worked to market them in the United Kingdom where they competed with popular British designs like the Adams and Webley revolvers. This Colt Lightning was manufactured in 1879 for the U.K. market and has a half-moon style front sight, "COLT D.A. 38" in an etched panel on the left side of the barrel, "COLT PT. F.A. MFG. CO. HARTFORD, CT. U.S.A./DEPOT 14. PALL MALL LONDON." on top of the barrel, the three patent dates on the left side of the action, "38 CAL" on the left side of the trigger guard, "S" on the front face of the cylinder, and checkered grips with embossed Rampant Colt trademarks. Matching serial numbers are on the back of the cylinder (partial), frame, trigger guard, back strap, and grips (handwritten). The bottom of the barrel and cylinder between the flute have London proof marks. The small parts are finished in bright fire blue, and the balance has nickel plating. The modern case has a label addressed similar to the barrel and has an English fitted interior with two empty cartridge blocks.