The included factory letter states this revolver was shipped on May 4, 1888, to Hartley & Graham of New York City in .44-40 caliber, with a 7 1/2 inch barrel, blue finish, and rubber grips. This shipment was for 10 guns. The .44-40 WCF Single Action Army has found a special place in the hearts of Peacemaker collectors. When introduced in 1877, the .44-40 WCF Single Action Army was intended to be used in conjunction with the another legendary Western icon, the Winchester Model 1873 Rifle, which used the same cartridge. "The .44-40 WCF was added to the list of Colt calibers for use with the popular Winchester rifle of the same caliber," wrote Colt author David Brown on page 96 of "The 36 Calibers of the Colt Single Action Army." He further states, "This combination of a rifle and a six shooter using the same cartridge made it possible for their user to buy only one kind of ammunition, and he could carry 'fodder' for both guns in the same cartridge belt." The left side of the barrel has the highly desirable "COLT FRONTIER SIX SHOOTER" in an acid etched panel. Around 1890, this highly desirable acid etched panel was replaced with a roll stamped marking. The barrel has the correct "44" caliber designation stamped in small font on the underside. The top of the barrel is stamped with the one-line Hartford address. The left side of the frame has the three-line patent dates marking. "44 CAL" stamped on the left side of the trigger guard. Matching full or partial serial numbers appear on the frame, trigger guard, and butt.