Advanced Gun System

The Advanced Gun System is a naval gun system developed and produced by BAE Systems Armaments Systems (formerly United Defense) for the Zumwalt-class destroyer of the United States Navy. The first magazine was delivered to the U.S. Navy on 25 May 2010.^[1]

Originally designed for mounting as a vertical gun, this 155 millimetres (6.1 in) gun has since been designed and produced for mounting within a more conventional turret arrangement. The AGS is designed to offer a weapon system capable of delivering precision munitions at a high rate of fire and at over-the-horizon ranges. As a vertical gun system it would only have been capable of firing guided munitions; the turret mounting will allow the use of unguided munitions as well.

The development of new ammunition for the AGS under the name Long Range Land Attack Projectile (LRLAP) is another major advance offered by the AGS program; it features separate projectile and propellant portions. The munitions are to be highly accurate, with a circular error probable (CEP) of 50 m (160 ft) or less. Lockheed Martin's flight test of the munition in July 2005 had a reported a flight distance of 59 nautical miles (109 km; 68 mi).

History

There has been research on extending the range of naval gunfire for many years. Gerald Bull and Naval Ordnance Station Indian Head tested an 11 in (280 mm) sub-caliber saboted long-range round^[2] in a stretched 16"/45 caliber Mark 6 gun in 1967.^[3] The Advanced Gun Weapon System Technology Program (AGWSTP) evaluated a similar projectile with longer range in the 1980s.^[2] After the battleships were decommissioned in 1992, the AGWSTP became a 5-inch gun with an intended range of 180 km (110 mi), which then led to the Vertical Gun for Advanced Ships (VGAS). The original DD-21 was designed around this "vertical gun", but the project ran into serious technology/cost problems and was radically scaled back to a more conventional 6.1 inch Advanced Gun System (AGS). One advantage of this move was that the gun was no longer restricted to guided munitions.

The naval gun system was developed and produced by BAE Systems Armaments Systems (formerly United Defense) for the Zumwalt-class destroyer of the United States Navy. The first magazine was delivered to the U.S. Navy on 25 May 2010.^[1]

Description

The AGS uses the same 155 mm caliber as most American field artillery forces, although it is unable to fire the same ammunition. Instead, a new range of ammunition was developed for this weapon. The gun barrel is 62 calibers long, and is able to fire the entire magazine (300+ rounds) with an average rate of fire of ten rounds per minute using a water cooled barrel. The AGS is to be mounted in a turret specifically designed for the Zumwalt class destroyer with fully automated ammunition supply and operation. The turret itself is designed to be stealthy, allowing for the entire length of the barrel to be enclosed within the turret housing when not firing.

A primary advantage of the AGS over the existing Mark 45 5" gun which equips most major surface combatants of the US Navy is its increased capability for supporting ground forces and striking land targets. With a 10 round per minute capacity, it offers the ability to deliver firepower close to that of a battery of six 155 mm howitzers. This initial strike fire power is possible by using a multiple round simultaneous impact (MRSI) firing tactic and does not equal the sustained fire power.^[4] This will increase the utility of vessels equipped with the weapon, especially in areas in which the US Navy exercises absolute sea supremacy.

Ammunition

The development of new ammunition for the AGS under the name Long Range Land Attack Projectile (LRLAP) is one of the major advances offered by the AGS program. The munitions are to be highly accurate, with a circular error probable (CEP) of 50 m (160 ft) or less. Lockheed Martin conducted a flight test of the munition in July 2005, reporting a flight distance of 59 nautical miles (109 km; 68 mi). The LRLAP ammunition features separate projectile and propellant portions. Total weight is 225 pounds (102 kg), including a bursting charge of 24 lb (11 kg). The maximum length of the combined munition is 88 in (220 cm), amounting to about 14 calibers.

Shortly after the USS Zumwalt (DDG-1000) was commissioned, the U.S. Navy moved to cancel the LRLAP due to excessive cost overruns. With the number of ships reduced from 32 to 3 examples, the per-unit cost of each LRLAP shot increased to $800,000-$1 million. This made the system untenable despite no significant performance issues. Other projectiles are being examined to replace the LRLAP, but since it is the only munition designed to be fired from the AGS, the barrel, software, cooling system, and automated magazines would have to be modified to accommodate a different round. It is not likely an LRLAP replacement could be put into service by the time Zumwalt enters operational service in 2018.^[5][6]

See also

• 8"/55 caliber Mark 71 gun – US Navy's Major Caliber Lightweight Gun (MCLWG) program, designed & tested in 1975, program terminated in 1978.

Notes and references

External links

• 155 mm/62 (6.1") Advanced Gun System (AGS)

Video links

• AGS employment in asymmetric warfare simulation scenario on YouTube
• AGS non-combatant evacuation simulation scenario on YouTube