United States of America
8"/23 (20.3 cm) Mark 7
Updated 07 October 2007
ASW Howitzer that could be used in place of the standard 4"/50 (10.2 cm) destroyer gun.  Not known how successful this weapon was, but none survived to World War II.  Made from a single alloy-steel forging.

Nomenclature note:  The USN 8"/15 (20.3 cm) Mark 8 was a Vickers 8" (20.3 cm) BL Mark 6 Model 1917 land howitzer issued to the US Marine Corps.
WNUS_8-23_mk7_pic.jpg

8"/23 Mark 7 Howitzer
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Gun Characteristics
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Designation 8"/23 (20.3 cm) Mark 7
Ship Class Used On Flush-deck destroyers of World War I
Date Of Design N/A
Date In Service 1918 (?)
Gun Weight 5,560 lbs. (2,522 kg)
Gun Length oa 190 in (4.826 m)
Bore Length 184 in (4.674 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist Uniform RH 1 in 15
Chamber Volume N/A
Rate Of Fire 3 - 4 rounds per minute
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Ammunition
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Type Bag
Projectile Types and Weights HE - 285 lbs. (129.3 kg)
Bursting Charge HE - 70 lbs. (31.8 kg)
Projectile Length N/A
Propellant Charge N/A
Muzzle Velocity 650 fps (198 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun N/A
Note:  This weapon may have later used the standard 8" (20.3 cm) 260 lbs. (118 kg) shell.
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Range
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Elevation With 285 lbs. (129.3 kg) HE Shell
Range @ 20.8 degrees 2,600 yards (2,380 m)
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Mount / Turret Data
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Designation N/A
Weight  N/A
Elevation N/A
Elevation Rate Manual operation, only
Train about +150 / -150 degrees
Train Rate Manual operation, only
Gun recoil N/A
Loading angle N/A
Note:  This mounting was interchangeable with the standard 4"/50 (10.2 cm) Mark 12 mounting used on the flush-deck destroyers of World War I.
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Data from
"US Naval Weapons" by Norman Friedman
"A Treatise on Rifling of Guns" by Carl F. Jeansén
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"United States Naval Guns:  Their Marks and Modifications" Ordnance Pamphlet No. 127, December 1916, Second Revision June 1924
"Navy Ordnance Activities: World War, 1917-1918" by Navy Dept, United States, Bureau of Ordnance
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Gene Slover's Navy Pages
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Special help from Leo Fischer