This gun is interesting in that, unlike most USN weapons, the nominal caliber length was actually the overall length.
This or a similar gun was also used on the Argentine battleships of the Rivadavia class.
Of built up construction and used Welin breech blocks. The Mark 8 was built entirely out of nickel steel.
USS Maine B-10 being coaled
|Designation||6"/50 (15.2 cm) Marks 6 and 8|
|Ship Class Used On||Maine (B-10), Virginia (B-13), St. Louis (C-20) and Pennsylvania (ACR-4) classes|
|Date Of Design||about 1898|
|Date In Service||1903|
|Gun Weight||Without breech: 18,112 lbs. (8,216
With breech: 18,628 lbs. (8,450 kg)
|Gun Length oa||300.2 in (7.625 m)|
|Bore Length||about 294 in (7.468 m)|
|Twist||Increasing RH 0 to 1 in 25 at the muzzle|
|Chamber Volume||2,084 in3 (34.15 dm3)|
|Rate Of Fire||about 6 rounds per minute|
|Projectile Types and Weights||AP - 105 lbs. (47.7 kg)
Common Mark 20 Mods 0 to 4 - 105 lbs. (47.7 kg)
Anti-submarine - 105 lbs. (47.7 kg)
Illum Mark 22 Mod 1 - 95.40 lbs. (43.3 kg)
Illum Mark 23 Mods 1 and 2 - 96.0 lbs. (43.5 kg)
(see Note 2)
|AP - 2.4 lbs. (1.1 kg) Explosive D
Common before and during World War I - 4.0 lbs. (1.8 kg)
Common after World War I - 7.08 lbs. (3.2 kg) Explosive D
Anti-submarine - about 26 lbs. (11.8 kg)
|Projectile Length||Common - 22.7 in (57.7 cm)|
|Propellant Charge||World War I: 31 lbs. (14 kg) SPD
World War II: 38 lbs. (17.2 kg) SPD or SPDN
|Muzzle Velocity||2,800 fps (853 mps)|
|Working Pressure||17.0 tons/in2 (2,680 kg/cm2)|
|Approximate Barrel Life||N/A|
|Ammunition stowage per gun||Pennsylvania and Tennessee: 200
1) During World War I, a "flat-nose" shell was developed for use against submarines. The flat nose allowed the projectile to travel through water with reasonable accuracy. I lack other details of this projectile.
2) Some Common rounds had a burster of 6.25 lbs. (2.8 kg).
3) AP does not appear to have been in service during World War II.
|Elevation||With 105 lbs. (47.7 kg) AP Shell|
|Range @ 14.9 degrees
With original charge
|15,000 yards (13,720 m)|
|Range @ 15 degrees
With World War II charge
|16,000 yards (14,630 m)|
|6,000 yards (5,490 m)||
|9,000 yards (8,230 m)||
|12,000 yards (10,970 m)||
|Note: Data is for face-hardened Harvey plates and is from "Ordnance Data Sheets" of 1905.|
Maine (16), Virginia (12), St. Louis (14) and Pennsylvania (14): Mark 10
|Elevation||-10 / +15 degrees|
|Elevation Rate||Manually operated, only|
|Train||about +100 / -100 degrees|
|Train Rate||Manually operated, only|
1) The Mark 10 mounting was evaluated by Admiral Charles O'Neil, chief of the Bureau of Ordnance, as being "simple and strong, all parts are accessible, it has elevating gear on both sides and friction brakes in both the elevating and training gear, it works easily, one man being able to train and elevate with facility." However, it was apparently difficult to manufacture, with a third of the mountings being rejected by the bureau because of faulty recoil slides.
2) The hoists for these guns were electrically powered and could deliver one complete round every ten seconds to each gun.
3) The ships of the Maine class were reduced to eight guns in 1909. The removed guns were then reused on auxiliary ships during World War I.
15 August 2008 - Benchmark
03 November 2011 - Fixed typographical error