M197 electric cannon

2025-07-31T03:31:22Z

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{{Short description|20 mm Gatling-type rotary cannon}}
{{More footnotes needed|date=September 2010}}
{{Infobox weapon
| name = M197 Gatling gun
| image = JGSDF_AH-1S%2873482%29_M197_electric_cannon_at_Camp_Akeno_November_4%2C_2018_02.jpg
| image_size = 300
| caption =
| origin = United States
| type = [[Rotary cannon]]

| is_ranged = yes

| service = 1967–present
| used_by = [[United States Marine Corps]]
| wars =

| designer = [[General Dynamics]]
| design_date =
| manufacturer = [[General Dynamics Armament Systems]]
| unit_cost =
| production_date =
| number =
| variants =

| spec_label =
| weight = {{convert|132|lb|kg}}
| length = {{convert|1828|mm|in}}
| part_length = {{convert|1524|mm|in}}
| width =
| height =
| diameter =
| crew =

| cartridge = [[20×102mm]]
| caliber = [[20 mm]]
| barrels = 3-barrel (progressive RH parabolic twist, 9 grooves)
| action =
| rate = 750-1500 rpm<ref>{{Cite web |url=http://www.gdatp.com/armament_systems/mbw_M-197.html |title=General Dynamics Ordnance and Tactical Systems - Template |access-date=29 September 2015 |archive-url=https://web.archive.org/web/20151003071423/http://www.gdatp.com/armament_systems/mbw_M-197.html |archive-date=3 October 2015 |url-status=usurped }}</ref>
| velocity = {{convert|1,030|m/s|ft/s|}}
| range =
| max_range =
| feed =
| sights =
}}

The '''M197 electric cannon''' is a 20 mm three-barreled electric [[Gatling gun|Gatling-type]] [[rotary cannon]] used by the [[United States military]].

==Development==
The M197 electric cannon was developed primarily for use by [[United States Army]] [[military helicopter|helicopter]] [[gunship]]s. Development began in [[1967 in aviation|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 [[M61 Vulcan|General Electric M61 Vulcan]] cannon, with three [[Gun barrel|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]].

==History==
The M197 went into service on later marks of the [[AH-1 Cobra]], using either the [[U.S. Helicopter Armament Subsystems#AH-1 Cobra|M97]] or [[U.S. Helicopter Armament Subsystems#AH-1 Cobra|A/A49E-7]] armament subsystems, and was also fitted in a ventral [[Gun turret|turret]] on the [[U.S. Marine Corps]] [[OV-10 Bronco|YOV-10D Bronco NOGS]]. It is also the basis of the [[U.S. aircraft gun pods|GPU-2/A]] [[gun pod]], which incorporates the cannon, a [[battery (electricity)|battery]] and electric drive [[Electric motor|motor]], and 300 rounds of linkless ammunition.

In the Cobra, the weapon is supplied with a [[Magazine (firearms)|magazine]] of 700 linked rounds, with a total capacity including feeder system of 750 rounds. It has a cyclic rate of fire of 730+-50 rounds per minute. Standard practice is to fire the cannon in 30- to 50-round bursts. With extended automatic firing from a hover, the recoil is sufficient that the application of forward cyclic to maintain one's position over the ground is inadequate.

The M197 remains in use in the latest [[AH-1W SuperCobra]] and [[AH-1Z Viper]] gunships. Although the weapon's rotary drive is theoretically quite reliable, its ammunition feed has been anything but: Marine pilots initially reported an alarmingly high jam rate (sometimes greater than 30%).{{citation needed|date=October 2018}} The USMC and the manufacturer are aware of the problem and in 2011 a linkless feed system developed by Meggit Defense Systems was incorporated into the AH-1W and -1Z.{{citation needed|date=October 2018}} The system is capable of holding 650 +/-3 rounds in the storage unit with approximately 40 rounds in the feed chute.

The M197 is also mounted as a chin turret in Italy's [[Agusta A129 Mangusta]] CBT helicopter, with a capacity of 500 rounds.<ref>{{cite web |url=http://www.noblesmfg.com/20mm_ammunition_chute_programs_and_gun_systems.html |title=20MM Programs and Gun Systems - Nobles Manufacturing, Inc |access-date=2011-10-15 |url-status=dead |archive-url=https://web.archive.org/web/20080907174048/http://www.noblesmfg.com/20mm_ammunition_chute_programs_and_gun_systems.html |archive-date=7 September 2008 |df=dmy-all }}</ref>

The M197 is also mounted as a chin turret in South Korea's [[KAI LAH]] helicopter.

[[File:Fairchild AU-23A Peacemaker with XM197 20mm cannon.jpg|thumb|XM197 cannon on an [[Fairchild AU-23 Peacemaker|AU-23A]]]]
The M197 was also mounted into the [[Fairchild AU-23 Peacemaker|AU-23A]] as a handheld [[Door gunner|Door gun]].

The [[XM301]] was an improved M197 intended to be the gun on the later canceled [[Boeing-Sikorsky RAH-66 Comanche|RAH-66 Comanche]].

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

[[Iran]] has claimed downing one Iraqi [[MiG-21]] fighter on 14 February 1986 during the [[Iran–Iraq War]] using the M197 gun turret installed on its [[AH-1J International]]s. The cannon was also used during the "[[dogfight]]s" between Iranian AH-1Js and Iraqi helicopters (usually [[Mil Mi-24|Mi-24]]s and [[Aérospatiale Gazelle|Gazelle]]s).
{{see also|Iranian aerial victories during the Iran–Iraq war}}

==Ammunition==
{| class="wikitable"
|-
!width="80"| Designation
!width="55"| Type
! Projectile Weight [g]
!width="150"| Bursting charge [g]
! Muzzle Velocity [m/s]
! Description
|-
| M53 || API || align="center" | ?
| align="center" | 4.2 g incendiary
| align="center" | 1030 || Penetration 20mm at 25-degree impact and 100 meter range,<ref>{{Cite web| title=20mm - M50 Series | url=https://www.gd-ots.com/wp-content/uploads/2017/11/20mm-M50-Series.pdf | archive-url=https://web.archive.org/web/20190523190930/https://www.gd-ots.com/wp-content/uploads/2017/11/20mm-M50-Series.pdf | archive-date=2019-05-23}}</ref> 6.3mm RHA at 0-degree impact and 1000-m range.<ref>http://ugcsurvival.com/FieldManuals/FM%201-140%2019960329-Helicopter%20Gunnery.pdf, US Military ''Field Manual 1-140 Helicopter Gunnery''</ref>
|-
| M56 || HEI || align="center" | 102
| align="center" | 9 g HE (RDX/wax/Al) and 1.5 g incendiary
| align="center" | 1030 || Nose fuzed round, no tracer. Effective radius for causing casualties to exposed personnel is 2 meters with fragmentation hazard out to 20 meters. Penetration 12.5mm RHA at 0 degree obliquity at 100m range
|-
| M242 || HEI-T || align="center" | ?
| align="center" | ?
| align="center" | ? || Similar to M56 series of HEI rounds, but with a tracer element
|-
| M246 || HEI-T || align="center" | 102
| align="center" | 8.0 g HE<
| align="center" | ? || Nose fuzed tracer round fired by M168 AA gun, self-destruct after 3 to 7 seconds of flight due to tracer burn-through.
|-
| [[M-940 20mm MPT-SD Round|M940]] || MPT-SD || align="center" | 105
| align="center" | 9 g A-4/RDX/wax
| align="center" | 1050 || Multi-purpose fuzeless round, HE charge is initiated by the incendiary charge on the nose on impact. Self-destruct due to tracer burn-through. Penetration 12.5mm RHA at 0 degree impact at 518 m range, or 6.3mm at 60 degrees and 940 m.
|-
|}

==See also==
* [[M61 Vulcan]]
* [[XM301]]
* [[M621 cannon]]—20×102mm gun mounted in helicopters as a chin turret

==References==
{{Reflist}}

==External links==
{{Refbegin}}
* [http://www.globalsecurity.org/military/systems/aircraft/systems/m197.htm GlobalSecurity.org M197]
* [https://web.archive.org/web/20070224040142/http://tri.army.mil/LC/CS/csa/cpm197.htm US Army Helicopter Weapons Team]
* [https://web.archive.org/web/20060824102021/http://www.mooredesign.com.au/acw/weapons/gun/m197/index.html The Aircraft Web Site]
* [http://www.gd-ots.com/armament_systems/mbw_M-197.html General Dynamics Ordnance and Tactical Systems M197 page]
{{Refend}}

{{Multiple Barrel Firearms}}
{{Modern Gatling Guns}}

{{Use dmy dates|date=June 2017}}

{{DEFAULTSORT:M197 Gatling Gun}}
[[Category:20x102mm]]
[[Category:Aircraft guns]]
[[Category:Multi-barrel machine guns]]
[[Category:Rotary cannon]]
[[Category:United States Marine Corps equipment]]
[[Category:Military equipment introduced in the 1960s]]

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M197 electric cannon