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| M197 Gatling gun | |
|---|---|
_M197_electric_cannon_at_Camp_Akeno_November_4%2c_2018_02.jpg) | |
| Type | Rotary cannon |
| Place of origin | United States |
| Service history | |
| In service | 1967–present |
| Used by | United States Marine Corps |
| Production history | |
| Designer | General Dynamics |
| Manufacturer | General Dynamics Armament Systems |
| Specifications | |
| Mass | 132 pounds (60 kg) |
| Length | 1,828 millimetres (72.0 in) |
| Barrel length | 1,524 millimetres (60.0 in) |
| Cartridge | 20×102mm |
| Caliber | 20 mm |
| Barrels | 3-barrel (progressive RH parabolic twist, 9 grooves) |
| Rate of fire | 750-1500 rpm[1] |
| Muzzle velocity | 1,030 metres per second (3,400 ft/s) |
TheM197 electric cannon is a 20 mm three-barreled electricGatling-typerotary cannon used by theUnited States military.
The M197 electric cannon was developed primarily for use byUnited States Armyhelicoptergunships. Development began in1967 after experience in theVietnam War revealed the inadequacy of the 7.62 mmMinigun for gunship use. The M197 is essentially a lightened version of theGeneral Electric M61 Vulcan cannon, with threebarrels instead of six. Its maximumrate of fire is one quarter that of the Vulcan, largely to limit itsrecoil for light aircraft and helicopter use. It shares the Vulcan's M50 and PGU series 20 mmammunition.
The M197 went into service on later marks of theAH-1 Cobra, using either theM97 orA/A49E-7 armament subsystems, and was also fitted in a ventralturret on theU.S. Marine CorpsYOV-10D Bronco NOGS. It is also the basis of theGPU-2/Agun pod, which incorporates the cannon, abattery and electric drivemotor, and 300 rounds of linkless ammunition.
In the Cobra, the weapon is supplied with amagazine 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 Cobra 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] 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 the Zulus.[citation needed] 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'sAgusta A129 Mangusta CBT helicopter, with a capacity of 500 rounds.[2]
The M197 is also mounted as a chin turret in South Korea'sKAI LAH helicopter.
The M197 was also mounted into theAU-23A as a handheldDoor gun.
TheXM301 was an improved M197 intended to be the gun on the later canceledRAH-66 Comanche.
The weapon's current contractor isGeneral Dynamics Armament Systems.
Iran has claimed downing one IraqiMiG-21 fighter on 14 February 1986 during theIran–Iraq War using the M197 gun turret installed on itsAH-1J Internationals. The cannon was also used during the "dogfights" between Iranian AH-1Js and Iraqi helicopters (usuallyMi-24s andGazelles).
| Designation | Type | Projectile Weight [g] | Bursting charge [g] | Muzzle Velocity [m/s] | Description |
|---|---|---|---|---|---|
| M53 | API | ? | 4.2 g incendiary | 1030 | Penetration 20mm at 25-degree impact and 100 meter range,[3] 6.3mm RHA at 0-degree impact and 1000-m range.[4] |
| M56 | HEI | 102 | 9 g HE (RDX/wax/Al) and 1.5 g incendiary | 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 | ? | ? | ? | Similar to M56 series of HEI rounds, but with a tracer element |
| M246 | HEI-T | 102 | 8.0 g HE< | ? | Nose fuzed tracer round fired by M168 AA gun, self-destruct after 3 to 7 seconds of flight due to tracer burn-through. |
| M940 | MPT-SD | 105 | 9 g A-4/RDX/wax | 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. |
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