12"/50 caliber Mark 8 gun

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12"/50 caliber Mark 8 gun
USS Guam (CB-2) firing main battery, 1944-45.jpg
USS Guam (CB-2) firing her 12"/50 guns during a training session sometime in 1944–1945.
Type Naval gun
Place of origin United States
Service history
In service 1944–1961[1][2]
Used by Alaska-class cruisers
Wars World War II
Production history
Manufacturer Naval Gun Factory, Midvale and Bethlehem Steel Corporation, Watervliet Arsenal[1]
Specifications
Barrel length Lua error in Module:Convert at line 1851: attempt to index local 'en_value' (a nil value). bore (50 cal)[1]

Shell 1,140 pounds (520 kg)
Caliber Lua error in Module:Convert at line 1851: attempt to index local 'en_value' (a nil value).[1]
Rate of fire 2.4–3.0 rounds per minute[1]
Maximum firing range 38,573 yards (35,271 m)[1]

The 12"/50 caliber gun Mark 8 was a US naval gun mounted on the Alaska-class cruisers.

Design and production

The gun was designed in 1939, and a prototype was tested in 1942. Unlike previous guns, such as the 16"/45 caliber guns used on the North Carolina class, which were completely made and assembled at the Naval Gun Factory in Washington D.C., the forgings for the Mark 8 were manufactured at the Midvale and Bethlehem Steel Corporation. They were then sent to the Naval Gun Factory for processing, which was followed by a trip to Watervliet Arsenal until they were 65% complete. Finally, the built-up guns were sent back to the Naval Gun Factory to be finished.

The gun was first deployed in 1944, on the lead ship of the Alaska class, USS Alaska (CB-1).[1] The two Alaska class ships each had nine Mark 8 guns mounted in three triple (3-gun) turrets, with two turrets forward and one aft, a configuration known as "2-A-1". Only two vessels of the class were completed, making them only applications of the Mark 8 12"/50 caliber gun.

Measurements

The Mark 8 weighed 121,856 pounds (55,273 kg) including the breech and was capable of an average rate of fire of 2.4–3 rounds a minute. It could throw a 1,140 lb. (517.093 kg) Mark 18 armor-piercing shell 38,573 yards (35,271 meters) at an elevation of 45°.[1][3] The previous 12" gun manufactured for the U.S. Navy was the Mark 7 version, used in the WWI era Wyoming-class battleships,[1] could only throw an 870-pound (390 kg) shell 24,000 yards (21,946 m), at an elevation of 15°[4] The Mark 8's significant improvement in firing weight and range over the Mark 7 gave it the honor of "by far the most powerful weapon of its caliber ever placed in service."[5] In fact, as a result of the decision to fire "super heavy" armor-piercing projectiles, the Mark 8's deck plate penetration was better and the side belt armor penetration equal to the older (but larger) 14"/50 caliber gun.

The "barrel life" of the Mark 8 guns was 344 shots, which was 54 more shots than the 16"/50 caliber Mark 7 gun found in the Iowa-class battleships.[1][6]

See also

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 Lua error in package.lua at line 80: module 'strict' not found.
  2. 1961 is the year the last remaining Alaska-class ship, Guam, was decommissioned.
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