5"/50 caliber gun

5 inch 50 caliber gun USS CHATTANOOGA C-16.jpeg
Chattanooga, 5"/50 caliber deck gun, probably port side forward.
Place of originUnited States
Service history
In service1904
Used by United States Navy
Production history
DesignerBureau of Ordnance
ManufacturerU.S. Naval Gun Factory
No. built
  • Mark 5: 87 (Nos. 200–286)
  • Mark 6: 64 (Nos. 293–356)
VariantsMark 5 Mods 0–3, Mark 6 Mods 0–2
  • Mark 5: 10,294 lb (4,669 kg) (with breech)
  • Mark 6: 10,550 lb (4,790 kg) (with breech)
LengthMarks 5 and 6: 255.65 in (6,494 mm)
Barrel lengthMarks 5 and 6: 250 in (6,400 mm) bore (50 calibers)

  • Mark 5: 60 lb (27 kg) armor-piercing
  • Mark 6: 50 lb (23 kg) armor-piercing
Caliber5 in (127 mm)
  • Mark 9: −10° to +15°
  • Mark 12: −10° to +25°
Traverse−150° to +150°
Rate of fire6–8 rounds per minute
Muzzle velocity
  • 50lb:3,000 ft/s (910 m/s)
  • 60lb:2,700 ft/s (820 m/s)
Maximum firing range19,000 yd (17,000 m) at 25.3° elevation

The 5"/50 caliber gun (spoken "five-inch-fifty-caliber") was the first long barrel 5-inch (127 mm) gun of the United States Navy and was used in the secondary batteries of the early Delaware-class dreadnought battleships, various protected cruisers, and scout cruisers. They were also refitted in the secondary batteries of the armored cruiser New York and the New Orleans-class protected cruisers. They were later used on cargo ships, store ships and unclassified auxiliaries during World War II as well as in emergency coastal defense batteries.[1]


The Mark 5, Nos. 200 – 286, was a 50 caliber naval gun of a simplified construction by combining the breech piece along with the chase hoop into one long tube that was shrunk on from the muzzle. Mod 1 was a Mod 0 gun that was relined with a conical nickel-steel liner and an additional gun-steel chase hoop that extended to the muzzle that was secured by a nickel-steel locking ring. Mod 2, gun No. 280, had a slightly different liner with Mod 3, gun No. 245, was a Mod 0 gun with its gun-steel tube replaced with a nickel-steel tube with a gun-steel chase hoop added that extended all the way to the muzzle. The Mod 3 gun had a longer chase hoop and shorter jacket compare to Mods 1 and 2.[1][2]

The Mark 6, gun Nos. 293 – 356, was the bag-ammunition equivalent to the Mark 5 gun. Mod 0, Nos. 323 – 356, had a single jacket constructed of nickel-steel, that replaced the jacket, chase hoop and locking ring of the Mark 5. Mod 1, Nos. 293 – 306 and 308, was built of gun-steel with a chamber of a different design with some external differences to fit it onto different mountings. The Mod 2, Nos. 307 and 309 – 322, had the same chamber as the Mod 0 but was otherwise almost identical to the Mod 1.[1][2]

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