Wright's Washington Navy Yard technical and historical archive

Weapon Design - Odds and ends

The Washington Navy Yard in the nation's capital has a impressive naval museum, with both indoor and outdoor displays.

One of the museum's exhibits is the 16 inch 50 calibre Mk2 gun designed and manufactured to arm six Lexington class Battlecruisers and six South Dakota class battleships cancelled by the 1922 Washington Naval treaty.
The gun rests on a rail carriage and dominates the landscape. Here is a brief overview on the weapon's performance.

Bore:
Length overall:
Length rifling:
Grooves:
Twist:
Weight Projectile:
Propellant charge:
Muzzle velocity:
Barrel life:
Max range:		16.0in (406.4mm)
816in (20,726mm)
675.992in (17,170.2mm)
96
1 in 50 to 1 in 32 or 1 in 32
2240lb (1016Kg)
648lb (294Kg)
2650f/s (808m/s)
?200 EFC
45,100yd/ 46o (41,240m/46o)
t

Lexington CC-1
Constellation CC-2
Saratoga CC-3
Ranger CC-4
Constitution CC-5
United States CC-6		South Dakota BB-49
Indiana BB-50
Montana BB-51
North Carloina BB-52
Iowa BB-53
Massachusetts BB54

Lexington and Constellation were to be fleet flagships. The prototype gun was test fired in April 1918, and 150 rifles were ordered in 1918-21. Seventyone had been completed and 44 were under construction when they were cancelled in February 1922. Twenty of the guns were transferred to the US Army between 1922 and 1924. The rest were kept in navy stocks until January 1941 when they were transferred to the Army for coastal defence. Click here for more infomation. - *
Three of the 128.15 ton weapons were kept by the Navy including the one on display at the Washington Navy Yard. During the design of the Iowa class battleship (BB61), the Mk2 rifles were considered for the main battery but the more powerful Mk7 16"50 calibre was fitted instead.

USS Lexington (port) and USS Saratoga (starboard) below completed as the world's first opperational Fleet Carriers.

Japanese Armor Plate vs. American 16" projectiles.

Another item of interest is this 26-inch armor plate which was intended for use in Japanese Yamato class battleships. (I theorize that this plate probably came from IJN Shinano, which was converted to an aircraft carrier during construction.) Found in the Kure Naval Base shortly after the end of World War II this plate was shipped to the Naval Proving Ground at Dahlgren, Virgnia for ballistics tests.
The damage to this particular section was inflicted by the impact of a standard U.S. Navy 16-inch armor piercing projectile.

During the test, two 406mm (Mk 8, Mod 6) AP with inert filler ("BL&P") projectiles were fired normal to the 660mm face plate intended for Shanano. One 16inch round failed to penetrate, but the second, fired with a higher muzzle volocity, went right throught. No damage was done to the projectile. According to the test, the Japanses VH face-hardended armor was approximately %10 inferior to the Amrerican type A armor.tt

For more info: click here for related site: Ballistic Tests on IJN SHINANO's Turret Face Armor.

The Award winning site, Imperial Japanese Navy Page has excellent resources concerning naval rifles and armor plate.
Due to the depth of information available, on the guns and armor, I won't even try to duplicate it here.

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Last updated: on November 12, 2001

*  The Complete Encyclopedia of Battleships by Tony Gibbons
Crescent Books, New York. 1983. Pg.234

t Naval Weapons of World War II by John Campbell
Naval Institute Press, Annapolis Md. 1985 Pg.116

tt Battleships, Axis and Neutral Battleships in World War II by William H. Garzke, Jr. Robert O. Dulin Jr
 Naval Institute Press, Annapolis Md 1985. Pg.94