M197 Gatling gun

Infobox Weapon
name= M197 Gatling gun


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service= 1967-present
used_by= United States Marine Corps
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manufacturer= General Dynamics Armament Systems
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caliber= 20 mm
barrels= 3
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rate= 730 rpm
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The M197 electric cannon is a three-barreled electric Gatling gun developed primarily for use by United States Army helicopter gunships.

Development of the M197 began in 1967 after experience in the Vietnam War revealed the inadequacy of the 7.62 mm Minigun for gunship use. The M197 is essentially a lightened version of the General Electric M61 Vulcan cannon, with three barrels instead of six. Its maximum rate of fire is one quarter that of the Vulcan, largely to limit its recoil for light aircraft and helicopter use. It shares the Vulcan's M50 and PGU series 20 mm ammunition.

The M197 went into service on later marks of the AH-1 Cobra, using either the M97 or A/A49E-7 armament subsystems, and was also fitted in a ventral turret on the U.S. Marine Corps YOV-10D Bronco NOGS. It is also the basis of the GPU-2/A gun pod, which incorporates the cannon, a battery and electric drive motor, and 300 rounds of linkless ammunition.

In the Cobra, the weapon is supplied with a magazine of 700 linked rounds. It has a cyclic rate of fire of 730 rounds per minute (± 50 rounds). Standard practice is to fire the cannon in 100-round bursts, allowing several minutes of cooling time between bursts.

The M197 remains in use in the latest AH-1W and AH-1Z Cobra gunships. Although the weapon's rotary drive is theoretically quite reliable, its ammunition feed has been anything but: Marine pilots report an alarmingly high jam rate (sometimes greater than 30%). The USMC and the manufacturer are aware of the problem, but no specific fix has been incorporated on the AH-1Z. In the meantime, crews have been trained in techniques intended to minimize the risk of jamming.

The weapon's current contractor is General Dynamics Armament Systems.

See also

*M61 Vulcan

References

* [http://www.globalsecurity.org/military/systems/aircraft/systems/m197.htm GlobalSecurity.org M197]
* [http://tri.army.mil/LC/CS/csa/cpm197.htm US Army Helicopter Weapons Team]
* [http://www.mooredesign.com.au/acw/weapons/gun/m197/index.html The Aircraft Web Site]
* [http://www.gdatp.com/products/PDFs/M197.pdf General Dynamics Armament and Technical Products]