The Cesare class guns were of Elswick Pattern "T" and those of the Duilio class were of Vickers Mark "G" type. Welin breech-blocks were used for both types. The Elswick guns were converted by Ansaldo and the Vickers guns by ODO. See the 12"/46 (30.5 cm) Model 1909 data page for the original construction details. The conversion consisted of boring out to remove the original A tube and apparently some of the wire. The remainder was shrunk on to a new A tube. It is possible that a shrunk or tupped inner A tube was also fitted.
Actual bore length of these reworked guns was 43.75 calibers.
Battleship Andrea Doria in 1940
Battleship Conte di Cavour pre-war
|Designation||320 mm/44 (12.6") Model 1934 and Model 1936|
|Ship Class Used On||OTO Model 1934: Cavour Class
Ansaldo Model 1936: Doria Class
|Date Of Design||1934 and 1936 (as remanufactured)|
|Date In Service||1940 (as remanufactured)|
|Gun Weight||64 tons (69,672 kg)|
|Gun Length oa||about 571 in (14.500 m)|
|Bore Length||551.2 in (14.000 m)|
|Rifling Length||about 446 in (11.320 m)|
|Twist||Uniform RH 1 in 30|
|Chamber Volume||about 21,360 in3 (450 dm3)|
|Rate Of Fire||2 rounds per minute|
|Projectile Types and Weights||AP - 1,157 lbs. (525 kg)
HE - 1,010 lbs. (458 kg)
|Projectile Length||N/A (probably 4.46 calibers)|
|Propellant Charge||386 lbs. (175 kg)|
|Muzzle Velocity||2,723 fps (830 mps)|
|Working Pressure||19.5 tons/in2 (3,100 kg/cm2)|
|Approximate Barrel Life||150 rounds|
|Ammunition stowage per gun||100 rounds|
1)Propellant charges were in quarters.
2) The Naval Museum in Venice, Italy, has a 320 mm APC projectile on display (Inventory #4402).
|Elevation||With 1,157 lbs. (525 kg) AP Shell|
|Range @ 27 degrees
(max elevation of Cavour)
|31,280 yards (28,600 m)|
|Range @ 30 degrees
(max elevation of Doria)
|32,150 yards (29,400 m)|
Cavour (2): Model 1934
Duilio (2): Model 1936
|Weight||Two-gun Turrets: 539 tons (548 mt)
Three-gun Turrets: 733 tons (745 mt)
|Elevation||As originally built: -5 / +20 degrees
|Elevation Rate||6 degrees per second|
|Train||about +120 / -120 degrees|
|Train Rate||5 degrees per second|
|Gun recoil||41 in (1.05 m)|
|Loading Angle||+12 degrees|
1) These turrets were originally hydraulically powered, but when modified were converted to electrical power.
2) The gun axes were 90 in (228.6 cm) apart in both the two-gun and the three-gun mountings.
03 November 2008 - Benchmark
26 May 2012 - Updated to latest template