Colt Mk 12 cannon

Colt Mk 12
Mk 12 cannon of a RNZAF Douglas A-4K Skyhawk.
Type
Place of origin	United States
Service history
In service	1950s – present
Wars	Vietnam War, Falklands War, Gulf War
Specifications
Weight	46.0 kg (101.4 lb)
Cartridge	20×110mm USN
Caliber	20 mm (0.787 in)
Action	Gas-operated reloading
Rate of fire	1,000 rpm
Muzzle velocity	1,010 m/s (3,300 ft/s)

The Colt Mk 12 was a 20 mm cannon widely used by the United States Navy after World War II.

The Mk 12 was an advanced derivative of the wartime Hispano HS 404 that had been used on British and some American fighter aircraft during World War II. It used a lighter projectile with a bigger charge for better muzzle velocity and higher rate of fire at the cost of hitting power. It entered U.S. Navy and U.S. Marine Corps service in the mid-1950s, replacing the earlier M3 cannon.

In service, the Mk 12 proved less than satisfactory. Although its muzzle velocity and rate of fire were acceptable, it was inaccurate and frequently unreliable. Pilots of the F-8 Crusader over North Vietnam, in particular, appreciated the presence of the cannon, but jams and stoppages were common, especially following hard dogfighting maneuvers.

Nevertheless, the Mk 12 was standard cannon armament on gun-armed American naval fighters from the early 1950s to the early 1970s, including the F4D Skyray, F3H Demon, A-4 Skyhawk, F-8 Crusader, F-11 Tiger and early navy versions of the LTV A-7 Corsair II.

International customers of the A-4 Skyhawk, F-8 Crusader, and the A-7 Corsair II also used the Mk 12 cannon: Argentina, Australia, Brazil, France, Kuwait, Malaysia, New Zealand, the Philippines and Portugal. The only exception were Israel and Singapore. The Israeli Air Force replaced the Mk 12 cannon with the French 30 mm DEFA cannon (a revolver design) in its Skyhawks, the Republic of Singapore Air Force fitted the British 30 mm ADEN cannon (another revolver). Indonesia later bought some used A-4s from Israel.