This is an excellent example of a Colt/Auto Ordnance Model 1921/28 "U.S. Navy" overstamp submachine gun. In 1921 Colt Firearms manufactured approximately 15,000 Model 1921 Thompson Submachine Guns for the Auto-Ordnance Corporation. They originally had a cyclic rate of 800 rounds per minute and were not fitted with Cutts compensators. Between 1926 and 1928 the Marine Corps obtained a few Model 1921 Thompsons, and based on their combat experience in Nicaragua and China, they recommended a reduction in the rate of fire to a more manageable level. In response to the Marines, the Auto-Ordnance Corp. modified the design to reduce the rate of fire to approximately 600 rounds per minute and added a Cutts compensator to reduce muzzle rise during firing. In 1928, Auto-Ordnance redesignated/remarked the modified 1921 guns as "Model 1928" and restamped "U.S. NAVY" over the original "MODEL OF 1921" markings, creating this "over stamp" model for sales purposes. The left side of the receiver is now stamped with an "8" over the "1" in "1921". Although the guns were marked "U.S. NAVY", most of the Model 1928 Thompsons were sold to law enforcement, as in this case. The left side of the trigger frame has the second style "FULL/AUTO", "SINGLE" and "FIRE-SAFE" markings found on most Colt/AO Model 1928 guns. The left side of the receiver is stamped with the serial number "NO 7439". The top rear section of the receiver is affixed with a small gold/black label that reads: "PROPERTY OF/BOROURGH OF DOWNINGTOWN/PENNA/0004." The left rear side is marked: "THOMPSON SUBMACHINE GUN/CALIBRE .45 AUTOMATIC COLT CARTRIDGE/MANUFACTURED BY/COLT'S PATENT FIRE ARMS MFG. CO./HARTFORD, CONN., U.S.A." The right side is roll-stamped: "AUTO-ORDNANCE CORPORATION./NEW YORK, U.S.A." followed by the six-line block of patent dates. The top of the receiver is stamped with the Thompson "Bullet" trademark. The bottom of the trigger frame is stamped with the matching serial number "NO 7439". This example has the second model Cutts compensator with Cutts trademarks and patent markings on the top. The gun has the 1928 internal components which include: (1) a 1928 second style blued weighted actuator, (2) long one piece pilot rod. (3) small diameter recoil spring. The gun has the original finned barrel, vertical walnut fore-grip and folding Lyman leaf rear sight. The internal components on the trigger frame and stock are finished bright. This lot includes one Thompson 50-round, "L" marked drum, and three early Colt production blued 20-round stick magazines with the early 1921 date and an original nickel plated oiler in the buttstock. It also includes an original brass Thompson cleaning rod, an original spare parts kit stored in its original small blue tin storage box, which includes two extra firing pins, an extractor, internal springs and bore brush. It all comes housed in an storage case with blue felt lining. This Thompson is listed by serial number in Herigstad's "Colt Thompson Submachine Gun Serial Numbers and Histories," Vol. 1 as being delivered to the Downingtown, Pennsylvania Police Department (page 758).