This is a highly desirable early production U.S. military contract Colt Model 1911 semi-automatic pistol with the early slide markings, early nitre blue finished small parts, and the rare and very desirable early small serial number markings. This early pistol was manufactured in the first full month of production, being assembled on 25 January 1912. It was shipped to the Commanding Officer of Springfield Armory on Feb. 3, 1912, in a shipment of 200 pistols. The pistol has the lustrous high polish Colt commercial blue finish with the nitre blue finish on the thumb safety, slide stop, hammer, trigger, mainspring cap and barrel bushing. The high polish finish was replaced by the military "dull finish" blue at approximately serial number 2,400 on April 24, 1912. The slide is marked with the early two-line, two-block Colt factory address and patent dates and circled Rampant Colt along with "MODEL OF 1911. U.S.ARMY" on the left and right of the slide respectively. The right side of the frame ahead of the trigger guard is stamped with the very early and highly desirable small serial number markings of "No. 151" which were changed at to "N" with an underlined "o" at serial number 4501 and then moved between the grip and slide stop hole at serial number 7501. The left side stamped with the smaller "UNITED STATES PROPERTY" which had only just been adopted at serial number 104, and the circled "WPG" monogram of Ordnance Inspector Walter G. Penfield above the magazine release. It is fitted with a blade front sight and round top notch rear sight, checkered wide hammer, checkered slide stop, thumb safety, and magazine catch, short grip safety, smooth mainspring housing, lanyard loop, diamond pattern checkered grips, and a replacement two-tone magazine with lanyard loop on the bottom. The early unmarked pattern barrel is high polish on the tube and brush blued on the rear portion.