This weapon grew out of a design study for replacing the 5"/38 (12.7 cm) Mark 12 and was originally planned for the never-built Montana Class battleships. They actually made their first service debut aboard the large aircraft carriers of the Midway class (CVB-41) and later on the gunnery training ship USS Mississippi AG-128 (ex BB-41).

This gun was not as popular as the 5"/38 (12.7 cm) Mark 12, probably because the larger and heavier projectiles and cartridge cases resulted in faster crew fatigue. Essentially, this weapon was simply a longer version of the 5"/38 (12.7 cm) Mark 12 and should not be confused with the later 5"/54 (12.7 cm) weapons which included automatic ammunition feeding provisions.

These guns were gradually removed from the Midway class carriers as weight compensation for growth in other areas. Some of these mountings were then reused on new-construction Japanese destroyers.

At least one mounting still exists at the White Sands Missile Range in New Mexico.

Nomenclature Note: This was the last USN 5" (12.7 cm) weapon that was best known by the gun barrel Mark number designation, although a few works refer to it per its Mark 39 mounting designation. All subsequent 5" (12.7 cm) designs are known by the mounting Mark number designation. See USN Naval Gun Designations for more information.

Gun Characteristics

Designation 5"/54 (12.7 cm) Mark 16
Ship Class Used On USA
    Planned for Montana (BB-67) Class
    Midway (CVB-41) Class
    Mississippi (AG-128)

    Akizuki (DD-161, ex-USS DD-961) 1 and Murasme (DD-107) classes

Date Of Design 1940
Date In Service USN: 1945

Japan: 1960
Gun Weight 5,361 lbs. (2,432 kg) (without breech)
Gun Length oa N/A
Barrel and Bore Length 270.0 in (6.858 m)
Rifling Length 229.07 in (5.820 m)
Grooves N/A
Lands N/A
Twist Uniform RH 1 in 25
Length Of Rifling 229.07 in (5.820 m)
Chamber Volume 825.38 in3 (13.525 dm3)
Rate Of Fire 15 - 18 rounds per minute
  • ^Akizuki and her sister Teruzuki were laid down by Mitsubishi in 1959 to a modified USS Fletcher (DD-445) design.


Type Separate
Projectile Types and Weights 1a HC Mark 41 Mod 0 with PD fuze 2a: 69.33 lbs. (31.448 kg)
HC Mark 41 Mod 0 with MT fuze 2a: 69.45 lbs. (31.505 kg)
HC Mark 41 Mod 0 with VT fuze 2a: 69.19 lbs. (31.384 kg)
SP Common Mark 42 Mods 0 and 1 3a: 70.0 lbs. (31.75 kg)
Illum Mark 43 Mod 0: 70.0 lbs. (31.75 kg) 4a
Illum Mark 48 Mod 0: 69.2 lbs. (31.39 kg) 4a
Bursting Charge HC Mark 41: 7.75 lbs. (3.515 kg) Explosive D
SP Common Mark 42 Mods 0 and 1: 2.14 lbs. (0.97 kg) Explosive D
Projectile Length 26.0 in (66 cm)
Cartridge Case Type, Size and Empty Weight Mark 6: Brass, 127 x 836 mm, 13.04 lbs. (5.91 kg)
Propellant Charge 18.5 lbs. (8.19 kg) SPD or SPDN
Flashless: 19.0 lbs. (8.62 kg) SPDF
Muzzle Velocity 2,650 fps (808 mps)
Working Pressure 18.5 tons/in2 (29,137 kg/cm2)
Approximate Barrel Life 3,070 Rounds
Ammunition stowage per gun Midway and Montana: about 500 rounds
Akizuki: 330 rounds
  • ^The wide availability of ammunition for this and subsequent USN 5"/54 (12.7 cm) guns led the French to use these munitions for their own 127 mm (5") guns.
  • ^ 41 projectile bodies could be used with Point Detonating (PD), Mechanical Time (MT) or with proximity (VT) nose fuzes. When used with PD fuzes, they were considered to be HC rounds while those with MT and VT fuzes were considered as AA rounds. Rounds with MT or PD nose fuzes had an instantaneous contact type base fuze. A blind plug was used in place of the base fuze for those projectiles using VT nose fuzes.
  • ^Special Common Mark 42 had a windscreen and a thin hood and was strengthened to enhance its armor piercing qualities.
  • ^4.14.2The illumination round burns for approximately 50 seconds.
  • Bourrelet diameter was 4.985 inches (12.66 cm).


Range with 70 lbs. (31.75 kg) HC
Elevation Distance
10 degrees 13,000 yards (11,887 m)
15 degrees 16,300 yards (14,905 m)
20 degrees 19,000 yards (17,374 m)
30 degrees 22,500 yards (20,574 m)
35 degrees 24,100 yards (22,860 m)
45 degrees 25,909 yards (23,691 m)
AA Ceiling @ 85 degrees 51,600 feet (15,728 m)

Mount/Turret Data

Designation 1b 2b Single Mount 3b
    Midway (18) 4b, Akizuki (3) and Murasme (3): Mark 39

Twin Mount
    Montana (10): Mark 41

Weight Mark 39: 33 tons (33.5 mt)
Mark 41: N/A
Elevation -10 / +85 degrees
Rate of Elevation 15 degrees per second
Train about -150 / +150 degrees
Rate of Train 30 degrees per second
Gun Recoil 19 in (48.3 cm)
  • ^Both single and twin mountings were base ring types and had projectile and powder hoists on the axis of the mount.
  • ^These mountings used amplidyne all-electric power drives.
  • ^A minimum crew of sixteen men were required for the single mounting, with ten in the gun room and six in the handling room. Additional crewmen were required in the lower ammunition spaces.
  • ^USS Midway (CVB-41) and USS Franklin D. Roosevelt (CVB-42) had 18 guns as commissioned while USS Coral Sea (CVB-43) had 14 guns when commissioned. These carriers had the number of guns reduced over the years as compensation for weight growth in other areas, with all guns removed from Midway and Coral Sea by 1980. Franklin D. Roosevelt was retired in 1977 at which time she still retained two guns near the stern, one on each quarter.

Additional Pictures


"Jane's Pocket Book 9: Naval Armament" edited by Denis Archer
"Naval Weapons of World War Two" by John Campbell
"US Battleships: An Illustrated Design History," "US Carriers: An Illustrated Design History," "US Naval Weapons" and "The Naval Institute Guide to World Naval Weapon Systems 1991/92" all by Norman Friedman
"Battleships: United States Battleships, 1935-1992" by W.H. Garzke, Jr. and R.O. Dulin, Jr.
"Illustrated Complete Ship's Data JMSDF 1952-98" by Ishibashi Takao
"Naval News in Pictures" Warship International No. 2, 1987
"Naval Ordnance and Gunnery - 1952" Navpers 16116-B
"U.S. Explosive Ordnance: Ordnance Pamphlet 1664 - May 1947" by Department of the Navy
White Sands Missile Range
Special help by Leo Fischer

Page History

12 August 2008 - Benchmark
23 March 2012 - Added source and photograph of Yudachi
16 April 2013 - Added link to French 127 mm datapage
22 November 2014 - Added note about Mark 39 designation
18 May 2015 - Redid painting of USS Montana
12 January 2019 - Converted to HTML 5 format, reorganized notes and added mounting sketch
14 April 2020 - Corrected typographical error, minor formatting changes, added data regarding removal of guns and photograph of Midway port side