Breda Model 35
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The Breda 20/65 mod.35, also simply known as 20 mm Breda or Breda Model 35, among other variations, was an Italian 20 mm anti-aircraft gun produced by the Società Italiana Ernesto Breda of Brescia company during the 1930s and early 1940s. Wikipedia
Action: Gas-operated
Barrels: 1
Caliber: 20 mm (0.79 in)
Crew: 3–6
Effective firing range: 1,500 m (4,900 ft) (against aerial targets)
In service: 1935–ca 1985
Maximum firing range: 5.5 km (3.4 mi)