Mk 44 Bushmaster II 30/40mm Automatic Cannon / Mk 46 Weapon Station

The Mk 44 is a medium caliber automatic cannon capable of being used in fighting platforms to include ground vehicle, naval and aircraft applications. This weapon can be converted to fire 40mm rounds with a change of barrels and minor changes to the feeder assembly. The conversion has been described as relatively simple by the manufacturer, for example being able to be performed by the crew on the ship on which the weapon is mounted.

One of the Mk 44 chain gun's intended applications is on the Marine Corps Expeditionary Fighting Vehicle (EFV), formerly known as the Advanced Attack Amphibious Vehicle (AAAV). The Expeditionary Fighting Vehicle's (EFV) Mk 46 Mod 0 Weapon Station incorporates the 30mm Mk 44 automatic gun, as well as, a 7.62mm coaxial machine gun. The Mk 46 Mod 0 Weapon Station as designed will carry 215 ready rounds of 30mm and 600 ready rounds of 7.62mm ammunition. The load out has been described as sufficient to complete the intended EFV mission. Since 1997, the EFV Program has been a leader in developing the Mk 44, which has been adopted by other DoD acquisition programs including the USN LPD-17 amphibious ship class and the USAF AC-130 Gunship programs.

The Mk 44 Cannon and Mk 46 Weapon Station nomenclature has been the source of some ambiguity and confusion in official publications, which have at times used the nomenclature interchangeably. This weapon should not be confused with the Mk 46 Mod 0 5.56mm Lightweight Machine Gun, a compact, belt-fed machine gun manufactured by FN Herstal of Belgium. It should also not be confused with the the 3,000 rounds-per-minute 7.62 mm GAU-17/A rotary barrel machine gun.

The Mk 44 has proven performance featuring dual feed Bushmaster Chain Gun® technology. It was designed to fire all existing types of 30mm x 173mm ammunition and can be chambered for 30x170mm Rarden. It is also capable of being easily converted to fire Super Forty 40mm ammunition for built in growth capability. ATK's Bushmaster series was already the gun system of choice for numerous North American and European armored vehicles including those of the Swiss, Polish and Finnish armies, as well as armored vehicles of the United States Army and Marine Corps.

On 1 November 2004, ATK received an $8.8 million contract for Research, Development, Testing and Evaluation (RDT&E) of a modified Mk 44 30mm Automatic Cannon for use by the U.S. Air Force Special Operations Command on its AC-130U gunships. The AC-130U incorporates side-firing cannons to provide surgical firepower or area saturation against hard targets such as armored vehicles. This was the first time the Mk 44 would be flown on-board a fixed-wing aircraft. The Mk 44 was already the weapon system of choice for the U.S. Marine Corps Advanced Amphibious Assault Vehicle and other armored vehicles. ATK would develop and incorporate unique gun characteristics required by the Special Operations Command to meet its demanding mission requirements. As a leading provider of chain gun technology, ATK was uniquely qualified to develop and integrate next-generation capabilities that meet the ever-increasing performance requirements of the Special Forces.

The design simplicity of the Mk 44, its positive round control, ease of maintenance and constant velocity ammunition feed made it the low-risk, proven weapon system the Air Force could rely on for effective fire support. The weapon system fires 30mm rounds and would enhance the aircraft's ability to destroy enemy armored vehicles by significantly increasing its stand-off distance while providing more firepower on target.

The Mk 44 cannon has also been designed for shipboard applications. The LPD-17 featured the Mk 46 Mod 1 Weapon Station with the Mk 44 30mm gun system, a two-axis stabilized chain gun that can fire up to 250-rounds per minute. The Mk 46 Mod 1 system uses a forward looking infrared sensor, a low light television camera, and laser range finder with a closed-loop tracking system to optimize accuracy against small, high-speed surface targets. The Mk 46 Mod 1 Weapon Station can also be operated locally at the gun's weapon station (turret) or fired remotely by a gunner in the ship's Combat Information Center, has reduced armor, no external periscopes and hatches, and a higher ready round capacity when compared to the EFV's Mod 0 station.

On 15 September 2005 it was announced that Alliant Techsystems (ATK) would provide the 30/40mm Mk44 Bushmaster Cannon system to MSI Defense Systems for integration onto its DS30M Mk 2 Naval Mounting. The DS30M Mk 2 mount is a single cannon naval mount that is gyro stabilized, electrically operated and self contained gun mounting featuring a choice of cannon, control mode and sights. It has low magnetic, radar and IR signatures and excellent ergonomic availability, reliability and maintainability (ARM).

The UK Royal Navy (RN) ordered a total of 26 systems for the new Type 23 Frigate, with deliveries scheduled to begin in late 2006. This was the first time ATK provided the Bushmaster for use on a RN vessel and it extended the Bushmaster's reach beyond armored vehicle applications to shipboard use. The gun systems would be used to enhance the Royal Navy's ability to counter fast attack craft (FAC) and fast inshore attack craft (FIAC). The RN and MSI selected ATK's Mk44 Bushmaster because of its significantly reduced dispersion rate and low ownership costs. In addition, the unique dual feed system of the Bushmaster series allows the operator to select different types of ammunition for use against a variety of targets. The safety, reliability and low life-cycle costs of the Bushmaster system added to its overall value.