Description

First manufactured by Ansaldo in 1926, this gun was continually modified throughout the 1930s by both Ansaldo and Odero-Terni-Orlando (OTO). Fired separate ammunition and used horizontal sliding breech-blocks.

These guns in the twin mountings suffered from excessive dispersion which seems to have been the result of mounting the barrels too closely together. On later destroyers, a single 120 mm/50 (4.7") mounting was used to replace obsolete 120 mm/15 (4.7") star-shell howitzers and thus improved the ship's firepower.

Gun Characteristics

Designation 120 mm/50 (4.7")
Ansaldo Models: 1926, 1936, 1937 and 1940
OTO Models: 1931, 1933 and 1936
Ship Class Used On See Mounting Data, below
Date Of Design 1926
Date In Service 1936
Gun Weight 5.1 tons (5,552 kg)
Gun Length oa 252.0 in (6.400 m)
Bore Length 236.2 in (6.000 m)
Rifling Length 195.2 in (4.958 m)
Grooves about 36
Lands N/A
Twist Uniform RH 1 in 30
Chamber Volume 920.1 in3 (15.08 dm3)
Rate Of Fire 6 - 7 rounds per minute

Ammunition

Type Separate
Projectile Types and Weights HE: 51.8 lbs. (23.15 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge 21.4 lbs. (9.7 kg)
Muzzle Velocity 3,117 fps (950 mps)
Later reduced to 3,018 fps (920 mps)
Working Pressure 20.0 tons/in2 (3,150 kg/cm2)
Approximate Barrel Life N/A
Ammunition stowage per gun Navigatori: 182 rounds 1
Others: N/A
  1. ^Outfit for Navigatori class was 408 AP, 672 HE, 120 incendiary and 100 star shells plus an unspecified number of ready rounds.

Range

Range with 51.8 lbs. (23.15 kg) HE
Elevation Muzzle Velocity Distance
35 degrees 3,018 fps (920 mps) 19,900 yards (18,200 m)
45 degrees 21,430 yards (19,600 m)
3,117 fps (950 mps) 24,060 yards (22,000 m)

Mount/Turret Data

Designation
  • Twin Mountings 1
    • Navigatori (3), Dardo (2) and Folgore (2): Ansaldo 1926
    • Soldati (2): Ansaldo 1936 and 1937
    • Maestrale and Oriani Classes: OTO 1931 and 1936
    • Conte Di Cavour Class: OTO 1933 2
  • Single Mounting
    • Soldati (1): Ansaldo 1940
Weight Ansaldo 1926: 19.92 tons (20.24 mt)
Ansaldo 1936 and 1937: 21.26 tons (21.60 mt)
Ansaldo 1940: 11.81 tons (12.00 mt)
OTO 1931: 17.37 tons (17.65 mt)
OTO 1933: 33.46 tons (34.00 mt)
OTO 1936: 22.44 tons (22.8 mt)
Elevation Ansaldo 1926: -10 / +45 degrees
Ansaldo 1936: -10 / +40 degrees
Ansaldo 1937: -10 / +42 degrees
Ansaldo 1940: -10 / +45 degrees
OTO 1931: -7 / +33 degrees
OTO 1933: -10 / +42 degrees
OTO 1936: -10 / +35 degrees
Elevation Rate N/A
Train about +150 / -150 degrees
Train Rate N/A
Gun recoil N/A
  1. ^Twin mountings had electric power for training and elevation.
  2. ^The OTO 1933 mountings used on the Conte Di Cavour class were different from the concurrent ones used on destroyers in that they were equipped with mechanical rammers, better shell and propellant hoists and had a much thicker shield.

Additional Pictures

Sources

Data from:

  • "Naval Weapons of World War Two" by John Campbell
  • "Italian Warships of World War II" by Aldo Fraccaroli
  • "Italian Super Destroyers" article by Elio Andò in "Warship Special 2: Super Destroyers" edited by Antony Preston

Other: