4"/50 caliber gun
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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. 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" x 50 = 200" or 5 meters)[1]
The gun weighed about 2.7 tonnes and used fixed ammunition (case and projectile handled as a single assembled unit) with a 14.5-pound (6.6 kg) charge of nitrocellulose propellant to give a 33-pound (15 kg) projectile a velocity of 2900 feet per second (884 m/s). Range was 9 miles (15 kilometers) at the maximum elevation of 20 degrees.[2]
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 like SS Stephen Hopkins.[3]
The 4"/50 caliber gun was mounted on:
- Caldwell class destroyers[4]
- Wickes class destroyers[5]
- Clemson class destroyers[6]
- Town class destroyers[7]
- United States S class submarines[8]
- the first seven Balao class submarines[9]
- USS Dolphin (SS-169)[10]
- rearmed submarines USS Salmon (SS-182) , USS Seadragon (SS-194), USS Gato (SS-212) and USS Robalo[11]
[edit] References
- 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.
- Lenton, H.T. and Colledge, J.J. (1968). British and Dominion Warships of World War II. Doubleday and Company.