This gun was air cooled and gas operated and seems to have been fairly efficient. It was derived from the 13.2 mm (0.52") M1931. Considered to have been a good weapon, although the low magazine capacity of 12 rounds meant frequent stoppages for change outs. An unusual feature was that the spent round was reinserted into the magazine.
These weapons were used for a time on the Australian warships HMAS Perth and HMAS Vendetta.
Another 20 mm weapon used by the Italians during World War II was the 20 mm/70 built by Scotti-Isotta Fraschini. This was used on the twin RM1939 mounting and a disappearing submarine mounting. This weapon had similar performance to the Breda.
| Designation | 20 mm/65 Models 1935, 1939 and 1940 |
|---|---|
| Ship Class Used On | Almost all |
| Date Of Design | 1935 |
| Date In Service | 1937 |
| Gun Weight | 159 lbs. (72 kg) |
| Gun Length oa | N/A |
| Bore Length | about 51.2 in (1.300 m) |
| Rifling Length | N/A |
| Grooves | N/A |
| Lands | N/A |
| Twist | N/A |
| Chamber Volume | N/A |
| Rate Of Fire | 240 rounds per minute cyclic about 120 rounds per minute practical |
| Type | Fixed |
|---|---|
| Weight of Complete Round | 0.705 lbs. (0.32 kg) |
| Projectile Types and Weights | HE: 0.295 lbs. (0.134 kg) |
| Bursting Charge | N/A |
| Projectile Length | N/A |
| Propellant Charge | 1.34 oz. (0.038 kg) |
| Muzzle Velocity | about 2,756 fps (840 mps) |
| Working Pressure | 17.8 tons / in2 (2,800 kg / cm2) |
| Approximate Barrel Life | 5,000 rounds |
| Ammunition stowage per gun | about 1,500 rounds |
| Elevation | Distance |
|---|---|
| 45 degrees | 6,000 yards (5,500 m) max. 2,730 yards (2,500 m) effective |
| AA Ceiling | 9,500 feet (2,900 m) |
| Designation | Model 1935 1: Stabilized Twin 2 Model 1939 3: Single Mounting Model 1940 4: Single Mounting |
|---|---|
| Weight | Model 1935: 5,137 lbs. (2,330 kg) Model 1940: 689 lbs. (312.5 kg) |
| Elevation | Singles: -10 / +90 degrees Twins: -10 / +100 degrees |
| Elevation Rate | Manual operation, only |
| Train | about +120 / -120 degrees |
| Train Rate | Manual operation, only |
| Gun recoil | N/A |
- ^Model 1935 was a twin mount with a stabilized line of sight. The left gun was mounted diagonally above the right gun (see picture above).
- ^Gun crew for twin mounts was one aimer and four loaders.
- ^Model 1939 was a little-used single mounting.
- ^Model 1940 was a free-swinging single mounting widely used on smaller ships.
Data from:
- "The Italian Navigatori Class, 1926" article by Elio Andò in "Warship Special 2: Super Destroyers" edited by Antony Preston
- "Naval Weapons of World War Two" by John Campbell
- "Battleships: Axis and Neutral Battleships in World War II" by W.H. Garzke, Jr. and R.O. Dulin, Jr.
- "Anatomy of the Ship: The Cruiser Bartolomeo Colleoni" by Franco Gay and Valerio Gay
Other:
- 21 September 2008
- Benchmark
- 26 May 2012
- Updated to latest template
- 23 September 2012
- Added picture of museum gun
- 08 September 2014
- Added note and photograph about HMAS Vendetta
- 08 December 2016
- Corrected typographical error