16-inch gun M1919

16-inch Coastal Defense Gun M1919
16-inch gun M1919 on barbette mount M1919, Fort Duvall, Hull, Massachusetts.
Type	Coastal Artillery
Place of origin	United States
Service history
In service	1920—1946
Used by	United States Army Coast Artillery Corps
Wars	World War II
Production history
Designer	US Army Ordnance Corps
Manufacturer	Watervliet Arsenal
Specifications
Weight	484 tons
Barrel length	50 calibers, 66 ft 8 in (20.32 m)
Shell	AP: 2,340 lb (1,060 kg) or 2,100 lb (950 kg); 850 lb powder charge
Caliber	16 in (406 mm)
Carriage	M1919 Barbette or M1917 disappearing, both fixed
Elevation	-7° to +65° (-5° to +30° disappearing carriage)
Traverse	360° (open and disappearing), 145° (casemated)
Muzzle velocity	2,700 ft/s (820 m/s)
Maximum firing range	49,100 yd (44,900 m) 27.9 miles (less with disappearing carriage)

The 16 inch Gun M1919 (406 mm) was a large coastal artillery piece installed to defend the United States' major seaports between 1920 and 1946. It was operated by the United States Army Coast Artillery Corps. Only a small number were produced and only seven were mounted; in 1922 and 1940 the US Navy surplussed a number of their own 16-inch/50 guns, which were mated to modified M1919 carriages and filled the need for additional weapons.

The first US 16-inch (406 mm) gun started construction in 1895 at Watervliet Arsenal. It was known as the M1895 and completed in 1902; only one was built. It was mounted on a disappearing carriage in Fort Grant on the Pacific side of the Panama Canal Zone in 1914, where it served until scrapped in 1943. The weapon's muzzle section was displayed at the Watervliet Arsenal museum, which closed in 2013.

The second 16-inch (406 mm) gun was the United States Army 50 caliber Model 1919 (M1919). The first of these was deployed to Fort Michie, Great Gull Island, New York on a unique all-around-fire M1917 disappearing carriage. An additional six of the Army-designed M1919 guns were built and deployed by 1927 in two-gun batteries on barbette carriages in the harbor defenses of Boston (Fort Duvall), New York City (Fort Tilden), and Pearl Harbor, Hawaii (Fort Weaver). The 16-inch gun M1919 was built using the wire-wound method, common in Europe but rare in the United States. Based on the Coast Artillery's experience operating heavy weapons in World War I, especially the French-made 400 mm (15.75 inch) Modèle 1916 railway howitzer, the M1919 barbette carriage was designed with an elevation of 65 degrees to allow plunging fire as enemy ships approached.