chambered for a 2 9/16-inch shotgun shell. To add further confusion, some of these early Model 12s have subsequently been modified, with their chambers lengthened to accept 2¾-inch shotgun shells, while others remain in their factory-stock chamber lengths. Careful inspection by a gunsmith is always recommended to determine whether or not it is safe to fire a modern 2¾-inch shotgun shell in older Model 12s. It is worth noting that while a 2¾-inch shell will often chamber in the short chambered Model 12s this will result in excessive pressure upon firing, and the fact that a 2¾-inch shell fits should never be taken as an indication that the chamber has been modified. Special production examples were produced by Winchester, the U.S. Repeating Arms Company, and Miroku after 1964 through 2006 through specialized gun collector purchase programs, but the Perfect Repeater shotgun was never mass-produced after 1964. The U.S. Repeating Arms Company (a subsidiary of FN) announced a complete closing of the New Haven, Connecticut factory facility in January 2006, thus ending the Model 12's long and illustrious career at the age of 95 years. Military use The United States armed forces used various versions of the Model 12 in World War I, World War II, Korea, and in the early part of the Vietnam War, until inventory was exhausted after the Model 12's initial production ceased in 1964. Versions of the Model 12 were type classified as the Model 12 or M12 for short. Approximately 20,000 Model 12 trench guns were purchased by the US Army in World War I, differing from the civilian version by having a shorter barrel, a perforated steel heat shield, and a M1917 bayonet adapter. More than 80,000 Model 12 shotguns were purchased during World War II by the United States Marine Corps, Army Air Forces, and Navy, mostly for use in the Pacific theater. Riot gun versions of the Model 12, lacking the heat shield and bayonet, were purchased by the Army for use in defending bases and in protecting Air Forces aircraft against saboteurs when parked. The Navy similarly purchased and used the riot gun version for protecting Navy ships and personnel while in foreign ports. The Marine Corps used the trench gun version of the Model 12 to great success in taking Japanese-occupied islands in the Pacific. The primary difference in Model 12 shotguns between the World War II trench gun version