An unsuccessful attempt by OTO to reduce the size of the 100 mm guns for submarine use. Replaced during World War II with standard deck-mounted 100 mm/47 submarine guns.

Gun Characteristics

Designation 100 mm/43 (3.9") Model 1927
Ship Class Used On Foca and Brin classes
Date of Design 1927
Date In Service 1937
Gun Weight N/A
Gun Length oa about 170 in (4.300 m)
Bore Length N/A
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire 8 - 10 rounds per minute


Type Fixed
Complete Round Weight N/A
Projectile Types and Weights HE: 30.4 lbs. (13.8 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge N/A
Muzzle Velocity 2,625 fps (800 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun N/A


Range with 30.4 lbs. (13.8 kg) HE
Elevation Distance
35 degrees 12,000 yards (11,000 m)

Mount/Turret Data

  • Single Mountings
    • Submarines (1): Model 1938 (?)
Weight N/A
Elevation -5 / +35 degrees
Elevation Rate Manually operated, only
Train 360 degrees
Train Rate Manually operated, only
Gun recoil N/A


Data from:

  • "Naval Weapons of World War Two" by John Campbell
  • "Italian Warships of World War II" by Aldo Fraccaroli


16 May 2006
11 September 2011
Corrected typographical error, redid photograph
26 May 2012
Updated to latest template gun