This is an exceptionally rare, very early Colt experimental/prototype Browning Automatic Rifle (BAR) manufactured circa late 1917/1918. This was a revolutionary fully automatic rifle that was developed by John Browning in 1917 and was adopted by the Army in 1918. As World War I dragged on, John Browning was working with Colt on design refinements for the BAR around the time of this rifle's manufacture. It was a man portable, highly reliable weapon that served in that end of WWI, throughout WWII, Korea and into Vietnam by the ARVN. This example is certainly one of the very early experimental or pre-production models as there are only a few markings and they are all hand stamped on top of the receiver. It is also stamped with the typical early factory experimental serial number of "XM20973". After being adopted by the US Military, all initial production was performed by the Winchester factory with Marlin-Rockwell and eventually Colt coming on line before the war ended. At the end of WWI, all three companies had manufactured approximately 52,000 guns. After WWI, Colt continued to manufacture a commercial Model 1918 that was extensively used by state and local law enforcement as well as the fledgling F.B.I. It even saw favor with the gangsters of the 1920s and 30s, especially Clyde Barrow and Bonnie Parker. As noted, this example has the hand stamped markings on top of the receiver that read: "XM20973/COLT PAT. FIREARMS/HARTFORD, CONN." It has all the early features such as the all blued metal finish with the internal components in the white. It is fitted with a very early (preproduction) rear sight that is graduated 2-28 (200-2800 yards) just like the 1903 Springfield rifle and a fixed blade front sight. It is also fitted with the very early squared and fully checkered forend, a walnut buttstock with the small pistol grip area and a smooth steel buttplate. It has early front sight base with no protective ears for the front sight and no provisions for a flash hider or bipod. It is complete with one high polish blued magazine, a jeep mountable leather storage case, canvas gunner's ammunition belt dated 1918, assistant gunner's ammunition belt dated 1918 and 2 metal ammo cans (empty) mounted on a vehicle rack.