United States of America
14"/50 (35.6 cm) Mark 7 and Mark 11
14"/50 (35.6 cm) Mark B
Updated 07 February 2008

The Mark 7 was a remanufactured 14"/50 (35.6 cm) Mark 4 with a smaller chamber, a shell centering cone, a single-slope band seat, uniform rifling and a tube locking ring.  The Mark 11 was the Mark 7 with the addition of chromium plating to the bore.  During the battleship modernization program of the 1930s, the 14"/50 (35.6 cm) Mark 11 was used to rearm the New Mexico and Tennessee Class Battleships, although the battleship Tennessee did not receive updated guns until 1942.

The problems with dispersion experienced with the 14"/50 (35.6 cm) Mark 4 guns seem to have been corrected with these rebuilt weapons.  At Surigao Strait, USS Tennessee (BB-43) and USS California (BB-44) reported pattern sizes of 300 to 400 yards (275 to 365 m) for six and nine gun salvos at 20,000 yards (18,300 m), which was not appreciably different than that achieved by the newer battleships during the war.

 The 14"/50 (35.6 cm) Mark B was the original gun intended for the North Carolina (BB-55) class battleships.  This weapon was the most powerful 14" (35.6 cm) gun ever designed by the United States and it was considerably simpler and lighter than the older 14"/50 (35.6 cm) gun.  The prototype of this weapon was never completed as its development was abandoned when the 14" (35.6 cm) treaty limit was rescinded in 1937, allowing these new battleships to be armed with 16"/45 (40.6 cm) guns.  For this reason, the 14" (35.6 cm) Mark B design was never assigned a standard numerical Mark designation.

Nomenclature note:  The 14" (35.6 cm) Mark A was the ballistic prototype of all 14" (35.6 cm) guns.  This prototype was developed around 1910 from a 13" (33 cm) Mark 2 bored out and relined for the larger projectiles.  The finished gun was 33 calibers long.  The 14" (35.6 cm) Mark C was a Mark 4 Mod 8 reworked as a prototype for the Mark 11.

The data that follows is specifically for the 14"/50 (35.6 cm) Mark 11 Mod 5 unless otherwise noted.

WNUS_14-50_mk11_California_1938_pic.jpg

Forward Turrets of USS California BB-44 in 1938
Note the Range Finders and Range Clock
U.S. Naval Historical Center Photograph # 80528

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Click here for additional pictures
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Gun Characteristics
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Designation 14"/50 (35.6 cm) Mark 7, Mark 11 and Mark B
Ship Class Used On Marks 7 and 11:  New Mexico (BB-40) and Tennessee (BB-43) classes

Mark B:  North Carolina (BB-55) (as originally designed)

Date Of Design Mark 7:  About 1930
Mark 11:  About 1935
Mark B:  About 1937
Date In Service Mark 7:  About 1935
Mark 11:  About 1940
Mark B:  N/A
Gun Weight 179,614 lbs. (81,473 kg) (including breech)

177,440 lbs. (80,487 kg) (without breech)

Gun Length oa 714.0 in (18.136 m) (overall)
Bore Length 700 in (17.780 m)
Rifling Length 607.4 in (15.427 m)
Grooves 92
Lands N/A
Twist Uniform RH 1 in 25
Chamber Volume 16,982 in3 (278.3 dm3)
Rate Of Fire Mark 7 and Mark 11:  About 1.75 rounds per minute
Mark B:  2 rounds per minute
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Ammunition
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Type Bag
Projectile Types and Weights AP Mark 16 Mods 1 to 11 - 1,500 lbs. (680.4 kg)
HC Mark 19 Mods 2 to 6 - 1,275 lbs. (578 kg)
HC Mark 22 Mod 0 - 1,275 lbs. (578 kg)
Bursting Charge AP Mark 16 - 22.90 lbs. (10.4 kg) Explosive D
HC Mark 19 - 104.21 lbs. (47.3 kg) Explosive D
HC Mark 22 - 104.21 lbs. (47.3 kg) Explosive D
Projectile Length Mark 16 AP - 56.00 in (142.2 cm)
HC Mark 19 Mods 2 to 6 - 56.00 in (142.2 cm)
HC Mark 22 Mod 0 - 56.00 in (142.2 cm)
Propellant Charge Full Charge - 420 lbs. (190.5 kg) SPD

Reduced Charge - 195 lbs. (88.5 kg) SPDN
Reduced Flashless Charge - 200 lbs. (90.7 kg) SPCG

Muzzle Velocity Full Charge - New Gun
   AP - 2,700 fps (823 mps)
   HC - 2,825 fps (861 mps)

Reduced Charge - New Gun
   AP - 1,935 fps (590 mps)
   HC - 2,065 fps (629 mps)

Working Pressure 18.0 tons/in2 (2,835 kg/cm2)
Approximate Barrel Life Mark 7:  175 to 200 rounds
Mark 11:  200 to 250 rounds
Mark B:  N/A
Ammunition stowage per gun 100 rounds
Notes:

1) HC Mark 22 was similar to the HC Mark 19 except that the rotating band was about 1.25 inches (3.2 cm) closer to the base.  HC projectile bodies could be used with Point Detonating (PD) or Mechanical Time (MT) fuzes.  When used with PD fuzes, they were considered to be HC rounds.  When used with MT fuzes, they were considered to be AAC rounds.  MT fuzes were probably set by hand on the loading trays.

2) When the chamber size was reduced during the modernization process, the propellant charge weight was cut by 50 lbs. (22.7 kg).  This meant that all 14" (35.6 cm) guns now shared the same charge, which had obvious advantages from a logistical point of view.  Even with the smaller charge, the 14"/50 (35.6 cm) gun still enjoyed a higher muzzle velocity and longer range over the shorter guns as well as better armor penetration capability.  However, reduced charges were smaller than those for the 14"/45 (35.6 cm) guns, in order to obtain the same muzzle velocity.

3) After 1941 AP rounds had a nominal 1.5 lbs. (0.68 kg) dye bag but this was allowed to be as large as 3.0 lbs. (1.36 kg) in order to bring underweight projectiles up to standard.  Battleships were assigned the following dye colors:

   New Mexico (BB-40) - Green
   Mississippi (BB-41) - Orange
   Idaho (BB-42) - Blue
   Tennessee (BB-43) - No Dye
   California (BB-44) - No Dye

4) Bourrelet diameter was 13.977 inches (35.5 cm).

5) Propellant was in four bags.

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Range
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Elevation
With 1,500 lbs. (680.40 kg) Mark 16 AP Shell
With 1,275 lbs. (578.34 kg) Mark 22 HC Shell
2.8 degrees
6,000 yards (5,490 m)
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5.0 degrees
10,000 yards (9,140 m)
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8.75 degrees
16,000 yards (14,630 m)
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10.0 degrees
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19,000 yards (17,374 m)
12.0 degrees
20,000 yards (18,290 m)
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15.0 degrees
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25,000 yards (22,860 m)
17.6 degrees
26,000 yards (23,770 m)
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20.0 degrees
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29,500 yards (26,975 m)
22.4 degrees
30,000 yards (27,430 m)
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25.0 degrees
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33,500 yards (30,632 m)
30.0 degrees 
(max elevation of turret)
36,800 yards (33,650 m)
36,600 yards (33,467 m)
35.0 degrees
39,800 yards (36,393 m)
39,500 yards (36,119 m)
40.0 degrees
42,100 yards (38,496 m)
41,500 yards (37,948 m)
45.0 degrees
43,000 yards (39,502 m)
42,585 yards (38,940 m)
Note:  Time of flight for AP Shell with MV = 2,525 fps (800 mps)
   10,000 yards (9,140 m): 13.0 seconds
   20,000 yards (18,290 m):  30.2 seconds
   30,000 yards (27,430 m):  53.3 seconds
   36,000 yards (32,920 m):  71.6 seconds
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Armor Penetration with 1,500 lbs. (680.40 kg) Mark 16 AP Shell
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Range
Side Armor
Deck Armor
Striking Velocity
Angle of Fall
0 yards (0 m) (new gun)
28.03" (712 mm)
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2,700 fps (823 mps)
0
0 yards (0 m) (avg. gun)
27.17" (690 mm)
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2,625 fps (800 mps)
0
5,000 yards (4,572 m)
23.66" (601 mm)
0.48" (12 mm)
2,326 fps (709 mps)
2.36
10,000 yards (9,144 m)
20.12" (511 mm)
1.27" (32 mm)
2,040 fps (622 mps)
5.61
15,000 yards (13,716 m)
16.76" (426 mm)
2.13" (54 mm)
1,789 fps (545 mps)
10.23
20,000 yards (18,288 m)
13.75" (349 mm)
3.02" (77 mm)
1,588 fps (484 mps)
16.33
25,000 yards (22,860 m)
11.27" (286 mm)
4.05" (103 mm)
1,455 fps (443 mps)
24.08
30,000 yards (27,432 m)
9.29" (297 mm)
5.31" (135 mm)
1,390 fps (424 mps)
33.0
35,000 yards (32,004 m)
7.82" (199 mm)
6.97" (177 mm)
1,402 fps (427 mps)
42.5
Note:  This data is from "Battleships:  United States Battleships 1935-1992" and is based upon the USN Empirical Armor Penetration formula.
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Mount / Turret Data
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Designation Three-gun Turrets
    New Mexico (4) and Tennessee (4)

Four-gun Turrets
   North Carolina (3) [as originally designed]

Weight Three-gun Turrets
    897 - 958 tons (911.35 - 973.21 mt)

Four-gun Turrets
   N/A

Elevation -5 / +30 degrees
Elevation Rate about 9 degrees per second
Train 306 max 297 min degrees
Train Rate about 2 degrees per second
Gun Recoil 48 in (1.219 m)
Loading Angle New Mexico class:  0 degrees
California Class:  +1 degree
Notes:

1) Unlike earlier USN 14" (35.6 cm) turrets, the guns in these mountings were individually sleeved.

2) As built, the New Mexico class had a maximum elevation of +15 degrees.  This was increased to +30 degrees during reconstruction in the 1930s.  The Tennessee class had a maximum elevation of +30 degrees as originally built.

3) Delay coils were fitted in the early 1930s which delayed the firing of the center gun by about 0.060 seconds (60 milliseconds).  These reduced the dispersion pattern by about half.

4) See 14"/50 (35.6 cm) Mark 4 data page for other information about these mountings.

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Data from
"Naval Weapons of World War Two" by John Campbell
"US Naval Weapons" and "US Battleships:  An Illustrated Design History" both by Norman Friedman
"Battleships:  United States Battleships, 1935-1992" by W.H. Garzke, Jr. and R.O. Dulin, Jr.
"The Big Gun:  Battleship Main Armament 1860-1945" by Peter Hodges
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"USS Massachusetts 1945 Gunnery Doctrine" USN BuOrd Publication
USS Tennessee and USS California Action Reports from Surigao Strait Battle
"U.S. Explosive Ordnance:  Ordnance Pamphlet 1664 - May 1947" by Department of the Navy
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Special help by Ed Jackson