4"/50 caliber gun
|4"/50 caliber naval gun|
|In service||1913 - 1945|
|Used by|| United States Navy
Royal Canadian Navy
|Wars||World War I, World War II|
|Variants||Mk 7, 8, 9 and 10|
|Weight||5,450 pounds (2,470 kg)|
|Length||206.5 inches (5.25 m)|
|Barrel length||200 inches (5 m) bore (50 calibres)|
|Shell||33 pounds (15 kg)|
|Calibre||4 inches (100 mm)|
|Elevation||-15 to 20 degrees|
|Traverse||-150 to 150 degrees|
|Rate of fire||8-9 rpm|
|Muzzle velocity||2,900 feet per second (880 m/s)|
|Maximum firing range||15,920 yards (14,560 m)|
The 4"/50 caliber Mark 9 gun (spoken "four-inch-fifty-caliber") was the standard low-angle, quick-firing gun for United States destroyers through World War I and the 1920s. It was also the standard deck gun on S-class submarines, and was used to rearm numerous submarines built with 3" guns early in World War II. United States naval gun terminology indicates the gun fired a projectile 4 inches (10 cm) in diameter, and the barrel was 50 calibers long (barrel length is 4 inch x 50 = 200 inches or 5 meters).
The built-up gun with a tube, full-length jacket, and side swing Welin breech block with Smith-Asbury mechanism weighed about 2.7 tons. Fixed ammunition (case and projectile handled as a single assembled unit) with a 14.5-pound (6.6 kg) charge of smokeless powder gave a 33-pound (15 kg) projectile a velocity of 2,900 feet per second (880 m/s). Range was 9 miles (14 km) at the maximum elevation of 20 degrees. Useful life expectancy was 500 effective full charges (EFC) per barrel.
Increasing awareness of the need for improved anti-aircraft protection encouraged mounting of dual purpose guns on destroyers beginning in the 1930s. The dual-purpose 5"/38 caliber gun became standard for United States destroyers constructed from the 1930s through World War II. United States destroyers built with 4"/50 caliber low-angle guns were rearmed with dual-purpose 3"/50 caliber guns. The 4"/50 caliber guns removed from destroyers were mounted on Defensively Equipped Merchant Ships of the British Merchant Navy and United States Merchant Marine like SS Stephen Hopkins. As S-boats were transferred from combat patrols to training duties from mid-1942 through 1943, their 4-inch guns were removed and used to re-equip front-line submarines built with 3"/50 caliber guns.
The 4"/50 caliber gun was mounted on:
- Cassin-class destroyers
- O'Brien-class destroyers
- Tucker-class destroyers
- Sampson-class destroyers
- Caldwell-class destroyers
- Wickes-class destroyers
- Clemson-class destroyers
- United States S-class submarines
- the first seven Balao-class submarines
- USS Dolphin (SS-169)
- numerous rearmed submarines including USS Salmon (SS-182), USS Seadragon (SS-194), USS Gato (SS-212), USS Silversides (SS-236) and USS Robalo (SS-273)
Many Mark 9 guns were supplied to the United Kingdom during World War II as part of Lend-lease, both individually and on naval and merchant ships. Caldwell, Wickes, and Clemson-class destroyers transferred under the Destroyers for Bases Agreement became British and Canadian Town-class destroyers.
- Campbell 1985 p.143
- Fairfield 1921 p.156
- Gardiner and Gray pp. 122-123
- Fahey 1939 p.14
- Fahey 1939 p.18
- Di Giulian
- Lenton and Colledge 1968 pp.90-92
- Campbell, John (1985). Naval Weapons of World War Two. Naval Institute Press. ISBN 0-87021-459-4.
- Fahey, James C. (1939). The Ships and Aircraft of the U.S. Fleet, War Edition. Ships and Aircraft.
- Fairfield, A.P. (1921). Naval Ordnance. The Lord Baltimore Press.
- Gardiner, Robert and Gray, Randal, Conway's All the World's Fighting Ships 1906-1921 Conway Maritime Press, 1985. ISBN 0-85177-245-5.
- Lenton, H.T. and Colledge, J.J. (1968). British and Dominion Warships of World War II. Doubleday and Company.
|Wikimedia Commons has media related to 4"/50 caliber gun.|
- DiGiulian, Tony, United States of America 4"/50 (10.2 cm) Marks 7, 8, 9 and 10 at Navweaps.com