The
Colt-Browning Mk 12 was a 20 mm
cannonA cannon is any tubular piece of artillery that uses gunpowder or other usually explosive-based propellants to launch a projectile. Cannon vary in caliber, range, mobility, rate of fire, angle of fire, and firepower; different forms of cannon combine and balance these attributes in varying degrees,...
widely used by the
United States NavyThe United States Navy is the sea branch of the U.S. Armed Forces. It is one of the seven uniformed services of the United States. As of 31 December 2008, the U.S. Navy had about 331,682 personnel on active duty and 124,000 in the Navy Reserve. It operates 283 ships in active service and more than...
after
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
.
The
Mk 12 was an advanced derivative of the wartime Hispano HS 404 that had been used on a variety of
AmericanThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
and
BritishThe United Kingdom of Great Britain and Northern Ireland is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, the northeastern part of Ireland, and many small islands...
fighter aircraftA fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets by dropping bombs. Fighters are small, fast, and maneuverable...
during
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
. It used a lighter projectile with a bigger charge for better
muzzle velocityA gun's muzzle velocity is the speed at which the projectile leaves the muzzle of the gun. Muzzle velocities range from subsonic for some pistols to more than 1,800 m/s for tank guns firing kinetic energy penetrator ammunition. The latter velocity is close to the limit achievable with chemical...
and higher rate of fire at the cost of hitting power. It entered U.S. Navy and
U.S. Marine CorpsThe United States Marine Corps is a branch of the United States armed forces responsible for providing force projection from the sea, using the mobility of the United States Navy to rapidly deliver combined-arms task forces. It is one of seven uniformed services of the United States...
service in the mid-1950s, replacing the Navy's earlier
M3 cannon.
In service, the Mk 12 proved less than satisfactory.
The
Colt-Browning Mk 12 was a 20 mm
cannonA cannon is any tubular piece of artillery that uses gunpowder or other usually explosive-based propellants to launch a projectile. Cannon vary in caliber, range, mobility, rate of fire, angle of fire, and firepower; different forms of cannon combine and balance these attributes in varying degrees,...
widely used by the
United States NavyThe United States Navy is the sea branch of the U.S. Armed Forces. It is one of the seven uniformed services of the United States. As of 31 December 2008, the U.S. Navy had about 331,682 personnel on active duty and 124,000 in the Navy Reserve. It operates 283 ships in active service and more than...
after
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
.
Development
The
Mk 12 was an advanced derivative of the wartime Hispano HS 404 that had been used on a variety of
AmericanThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
and
BritishThe United Kingdom of Great Britain and Northern Ireland is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, the northeastern part of Ireland, and many small islands...
fighter aircraftA fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets by dropping bombs. Fighters are small, fast, and maneuverable...
during
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
. It used a lighter projectile with a bigger charge for better
muzzle velocityA gun's muzzle velocity is the speed at which the projectile leaves the muzzle of the gun. Muzzle velocities range from subsonic for some pistols to more than 1,800 m/s for tank guns firing kinetic energy penetrator ammunition. The latter velocity is close to the limit achievable with chemical...
and higher rate of fire at the cost of hitting power. It entered U.S. Navy and
U.S. Marine CorpsThe United States Marine Corps is a branch of the United States armed forces responsible for providing force projection from the sea, using the mobility of the United States Navy to rapidly deliver combined-arms task forces. It is one of seven uniformed services of the United States...
service in the mid-1950s, replacing the Navy's 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 CrusaderThe F-8 Crusader was a single-engine aircraft carrier-based air superiority fighter aircraft built by Vought. It replaced the Vought F-7 Cutlass. The first F-8 prototype was ready for flight in February 1955, and was the last American fighter with guns as the primary weapon, principally serving in...
over
North VietnamNorth Vietnam, also called the Democratic Republic of Vietnam , was a communist state that ruled the northern half of Vietnam from 1954 until 1976....
, in particular, appreciated the presence of the cannon, but jams and stoppages were common, especially following hard
dogfightA dogfight, or dog fight, is aerial combat between fighter aircraft. Dogfighting first appeared during World War I, shortly after the invention of the airplane, and has since became a component in every major war despite beliefs after World War II that increasingly greater speeds and longer range...
ing maneuvers.
Nevertheless, the Mk 12 was standard cannon armament on gun-armed Navy and Marine Corps fighters from the early 1950s to the early 1960s, including the
F4D SkyrayThe American Douglas F4D Skyray was a carrier-based fighter/interceptor built by the Douglas Aircraft Company...
,
F3H DemonThe McDonnell F3H Demon was a subsonic swept-wing United States Navy carrier-based jet fighter aircraft. After severe problems with Westinghouse J40 engine that was ultimately abandoned, the successor to the F2H Banshee served starting in 1956 redesigned with the J71 engine...
,
A-4 SkyhawkThe Douglas A-4 Skyhawk is a carrier-capable ground-attack aircraft designed for the United States Navy and U.S. Marine Corps. The delta winged, single turbojet-engined Skyhawk was designed and produced by Douglas Aircraft Company, and later McDonnell Douglas...
,
F-8 CrusaderThe F-8 Crusader was a single-engine aircraft carrier-based air superiority fighter aircraft built by Vought. It replaced the Vought F-7 Cutlass. The first F-8 prototype was ready for flight in February 1955, and was the last American fighter with guns as the primary weapon, principally serving in...
and Navy versions of the
A-7 Corsair IIThe Ling-Temco-Vought A-7 Corsair II is a carrier-based subsonic light attack aircraft introduced to replace the United States Navy's A-4 Skyhawk, initially entering service during the Vietnam War. The Corsair was later adopted by the United States Air Force, to include the Air National Guard, to...
. Note: the guns were not mounted on the reconnaissance version of the Crusader, known as the F8U-1P or RF-8G Photo Crusader, which was completely unarmed. The Air Force version of the Corsair II, the A-7D, had a six-barreled M61A1 rotary 20mm cannon.
The Mk 12 is not the same as the Pontiac
M39 cannonThe Pontiac M39 was a 20 mm single-barreled revolver cannon developed for the United States Air Force in the late 1940s. It was used on a number of fighter aircraft from the early 1950s through the 1980s.-Development:...
used on the
F-100 Super SabreThe North American F-100 Super Sabre was a jet fighter aircraft that served with the United States Air Force from 1954 to 1971 and with the Air National Guard until 1979. As the first of the Century Series collection of USAF jet fighters, it was capable of supersonic speed in level flight...
,
F-101 VoodooThe McDonnell F-101 Voodoo was a supersonic military fighter flown by the USAF and the RCAF. Initially designed as a long-range bomber escort for the Strategic Air Command , the Voodoo was instead developed as a nuclear armed fighter bomber for the Tactical Air Command , and as a photo...
, F-5A Freedom Fighter and F-5E Tiger II fighters of the
U.S. Air ForceThe United States Air Force is the aerial warfare branch of the U.S. armed forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on 18 September 1947 under the National Security Act of 1947 - 80 P.L....
, despite the similar caliber.