M230 chain gun

The M230 Chain Gun is a 30 mm (30×113 mm), single-barrel chain-driven autocannon, using external electrical power (as opposed to recoil or expanding gas generated by the firing cartridge) to cycle the weapon between shots. It was designed and manufactured originally by Hughes Helicopters in Culver City, California.[1] The company was acquired by McDonnell Douglas Helicopters in 1985, which merged into Boeing Corporation in 1997. In 2002, it was sold again to Alliant Techsystems, which merged with Orbital Sciences Corporation in 2015 to form Orbital ATK and was, in turn, bought out by Northrop Grumman in 2018.[2] As of 2019, it is produced by Northrop Grumman Innovation Systems.[3]

M230 Chain Gun
An M230 Chain Gun mounted on a US Army AH-64 Apache at the Berlin Air Show 2018.
TypeChain gun
Place of originUnited States
Service history
In service1983–present
Used byUnited States, and other countries
WarsPersian Gulf War
War in Afghanistan
Iraq War
Production history
DesignerHughes Helicopters[1]
Designed1973[1]
ManufacturerHughes Helicopters (1975-1985)[1][2]
McDonnell Douglas Helicopters (1985-2002)[2]
Alliant Techsystems (2002-2015)[2]
Orbital ATK (2015-2018)[2]
Northrop Grumman Innovation Systems (2018-present)[2]
Produced1975–present[1]
VariantsM230LF
Specifications
Mass59.5 kg (130 lb)[3]
Length2,181 mm (85.9 in)[3]
Width277.2 mm (10.9 in)[3]
Height288.8 mm (11.4 in)[3]
Shell30×113 mmB
• M788 Target Practice (TP)
• M789 High Explosive Dual Purpose (HEDP)
• M799 High Explosive Incendiary (HEI)
Caliber30 millimetres (1.18 in) caliber
ActionOpen bolt
Rate of fire625 +/- 25 rpm[3]
Muzzle velocity805 m/s (2,641 ft/s)
Effective firing range1,500 m (1,640 yd)[4]
Maximum firing range4,000 m (4,370 yd)[5]

Development

In 1972, Hughes Helicopters began a company-funded research effort to design a single machine gun to fire the U.S. Army's M50 20 mm round.[6] By April 1973, the program had fired test rounds in more powerful 30 mm WECOM linked ammunition, from a prototype (A model). In January 1975 a model "C" was added, a linkless version for the proposed Advanced Attack Helicopter YAH-64; the helicopter was eventually adopted as the AH-64 Apache, with the model C as standard armament. The linked ammunition version was intended for use on the AH-1S Cobra as the M230E1, but was later dropped.[1]

Design
M789 HEDP 30 mm rounds being loaded into an AH-64D Longbow Apache in April 2007.

Apache and DAP mounts

The M230 Chain Gun is the "Area Weapon System" on the Boeing AH-64 Apache attack helicopter and is also used on the MH-60L Direct Action Penetrator (DAP). The M230 is mounted on the chin turret. It uses a 2 hp (1.5 kW) electric motor to fire 30 mm (1.2 in) linkless ammunition at a rate of 625 (±25) rounds per minute. The practical rate of fire is about 300 rounds per minute with a 10-minute cooling period as the gun is air cooled.[7] The gun has a positive cook-off safety for open bolt clearing, and double ram prevention. Spent casings are ejected overboard through the bottom of the gun.

The mount on the AH-64 uses secondary hydraulics to move the gun. Elevation is provided via a single hydraulic actuator located on the gun's centerline just forward of the pivot point. The gun is spring-loaded to return to its centerline stowed position with the barrel angled up about eleven degrees in the event of a loss of hydraulic power. This allows the gun, which is mounted below the copilot station, to collapse cleanly into its designed space between the pilot stations in the event of a hard landing. This prevents the gun from entering the pilots stations and becoming a hazard.

The Apache is capable of carrying up to 1,200 rounds for the gun in a device known as the 12-PAK, designed and manufactured by Meggitt Defense Systems, Inc. However, utilization by the US Army of a special internal fuel tank, the Robertson IAFS (known as the "Robby Tank" to the crews), reduces this capacity to 300 rounds.[8] The ammunition is loaded into the AH-64D Longbow Apache by armament personnel using an aircraft-mounted motorized loader and special ammunition handling tray. The AH-64A requires specialized ground support equipment for loading.[9]

The M230 is capable of firing the 30x113 rounds used in the ADEN cannon and DEFA cannon, however, the Lightweight 30 mm rounds (M788/M789/M799) used in the M230 are constructed with a light alloy as opposed to brass (ADEN) or steel (DEFA) cases to save weight and are in use with the US Army. The M230 rounds are not backwards compatible with weapons designed for the ADEN or DEFA rounds. The M788 rounds can be distinguished by the blue band near the nose, the M789 by a yellow stripe atop a black band and the M799 a red stripe atop a yellow band.[10][11] The M799 HEI round is not used by the US Army due to the danger of a round exploding in the gun barrel. The 30 mm M789 High Explosive Dual Purpose (HEDP) ammunition cartridge is the primary tactical round of the Apache AH-64 helicopter, widely used in current combat operations. The Apache's ability to provide accurate air support with minimal collateral damage led to increased use and volume demands for M789 ammunition.

The M789 is typically used in the M230. Each round contains 21.5 g (0.76 oz) of explosive charge sealed in a shaped-charge liner. The liner collapses into an armor-piercing jet of metal that is capable of penetrating 1 in (25 mm) of RHA at 500m. Additionally, the shell is also designed to fragment upon impact. The lethal radius against unprotected, standing targets is about 5 ft (1.5 m) under optimum conditions.

Variants

M230LF and MAWS

The M230LF, offered by Orbital ATK, is a more capable version of the Apache autocannon. Features include an anti-hangfire system, a delinking feeder that exploits linked ammunition, and an extended-length barrel, which results in greater muzzle velocity and hitting power from the same M789 HEDP and NATO standard 30 mm ADEN/DEFA projectiles. The rate of fire is reduced to 200 rounds/minute and overall length decreased to 84.0 inches (213 cm). The chain gun can be installed in an enclosed turret on patrol boats and ground vehicles.[12]

Oshkosh L-ATV in M1278 Heavy Guns Carrier JLTV configuration and fitted with an EOS R-400S-MK2 remote weapon system integrated with Orbital ATK's M230 LF 30 mm lightweight automatic chain gun

The MAWS (Modular Advanced Weapon System) lightweight gun system, developed in partnership with the U.S. Navy, utilizes a remotely operated M230LF in an open mount. It is controlled by a Remote Operator's Console (ROC)—with either dual grips or a joystick—from a touch panel display and extended day color TV.[13][14]

In February 2015, Oshkosh Defense and ATK conducted a firing demonstration of the M230LF on an Oshkosh M-ATV MRAP to demonstrate the viability and effectiveness of a medium caliber weapon system for light tactical vehicles. The live fire demonstration showcased improved accuracy in mobile engagements and improved lethality on the M-ATV using the gun, mounted on the R400S-Mk2, a 3-axis stabilized remote weapon station weighing less than 400 kg (880 lb). The addition of the 72.6 kg (160 lb) M230LF stabilized on the RWS provides mobile precise lethality, usually reserved for heavier combat vehicles, with exceptional off-road mobility and MRAP levels of protection.[15] Oshkosh has also fitted the M230LF to the L-ATV to fulfill the U.S. Army's light reconnaissance vehicle (LRV) role.[16]

Aircraft use
gollark: GTX 1050, the best GPU ever made.
gollark: Anyway, I should really figure out why MC freezes and crashes lots on my computron.
gollark: Galaxtone: why do you think [REDACTED] [DATA EXPUNGED]?
gollark: It's a HYPERBOLIC TESSELATION.
gollark: It's not like the C wild west, where everything buffer overflows like crazy.

See also

References
Notes
  1. Chinn, George M., 1987, pp. 453–454.
  2. "Trademark Assignment Abstract of Title". United States Patent and Trademark Office. 12 November 2018. Retrieved 28 April 2019.
  3. "Northrop Grumman M230 30mm chain gun fact sheet" (PDF). 2018. Retrieved 28 April 2019.
  4. Lee, T.W. (30 December 2008). Military Technologies of the World. ABC-CLIO. p. 118. ISBN 978-0-275-99536-2.
  5. "M230 Chain Gun". www.deagel.com. Retrieved 3 November 2017.
  6. Richardson & Peacock, 1992, pp. 38–40.
  7. "M230 Automatic Gun". globalsecurity.org. 2013. Retrieved 13 October 2013.
  8. "Robertson Aviation: Apache". Archived from the original on April 20, 2009. Retrieved 30 September 2011.CS1 maint: unfit url (link)
  9. "New Boeing Apache Ammunition Loading System Enters Service – December 15, 1998". boeing.mediaroom.com. 2013. Retrieved 13 October 2013.
  10. "30mm Cannon Ammunition". Federation of American Scientists. 8 January 1999. Retrieved 13 October 2013.
  11. Williams, Anthony G. (July 2010). "Military Cartridge Relationships". Military Guns & Ammunition. Archived from the original on 25 October 2012. Retrieved 13 October 2013.
  12. "Northrop Grumman 30mm M230LF Chain Gun" (PDF). 2018. Retrieved 28 April 2019.
  13. http://www.atk.com/Products/documents/108776_07_MAWS.PDF Archived November 4, 2011, at the Wayback Machine
  14. "Mk 51 MAWS" (PDF). National Defense Industrial Association (NDIA): Joint Armaments Conference, Exhibition & Firing Demonstration. May 2010. Archived from the original (PDF) on 21 February 2015. Retrieved 13 October 2013.
  15. Oshkosh, Orbital ATK, EOS unveiled strong integration capabilities during live fire demonstration - Armyrecognition.com, 19 February 2015
  16. Gun Truck: Oshkosh Unveils 30mm Chaingun JLTV For Army Recon - Breakingdefense.com, 9 September 2016
Bibliography
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