Advanced Gun System

The Zumwalt-class and AGS were designed and developed in the context of the United States battleship retirement debate. Battleship proponents argued that the battleships should not be decommissioned until an alternative method of providing naval gunfire support could be deployed, while others argued that such support was no longer needed in the era of missiles and aircraft. There has been research on extending the range of naval gunfire for many years. The 203 mm 8"/55 caliber Mark 71 gun was the US Navy's Major Caliber Lightweight Gun (MCLWG) program. The system was designed and tested in 1975, but the program was terminated in 1978. Gerald Bull and Naval Ordnance Station Indian Head tested an sub-caliber saboted long-range round in a stretched 16"/45 caliber Mark 6 gun in 1967. The Advanced Gun Weapon System Technology Program (AGWSTP) evaluated a similar projectile with longer range in the 1980s. and the navy had no plan to replace it. By early 2021, the navy was exploring replacing the AGS on Zumwalt-class ships with modules to carry hypersonic missiles. In March 2022, it was announced that both AGS would be removed from Zumwalt-class destroyers to enable installation of tubes to accommodate Common-Hypersonic Glide Body missiles. The switch was scheduled to begin in late 2023 as the ships undergo maintenance periods. AGS 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 May 25, 2010. == Description ==

The AGS uses the same 155 mm caliber as most American field artillery forces, although it is unable to fire the same ammunition due to differences in the size and shape of both projectile and firing charges. This was intended to increase the utility of vessels equipped with the weapon, especially in areas in which the US Navy exercises absolute sea supremacy. == Ammunition ==

AGS cannot use ammunition designed for existing artillery, so each type of ammunition must be designed and manufactured for AGS. The only type to be designed was the LRLAP. LRLAP procurement, however, was canceled and there are no plans to replace it. After some research had been abandoned into whether the M982 Excalibur guided munition could be adapted for use with the AGS, officials announced in January 2018 that there was now no plan for any replacement round for the AGS. Instead, Naval Sea Systems Command and the Chief of Naval Operations staff would "monitor new technologies" which might be used with the AGS system in the future. In particular he noted that the BAE Hypervelocity Projectile testing, a cross-service 127 mm (5-inch) naval and 155 mm land, low-drag self-guided Mach 7–capable round originally intended for railguns, was achieving range close to the original LRLAP specification while having superior rate of fire and accuracy. As of 2018, The HVP rounds were estimated to cost around $25,000 for a surface-to-surface 127 mm (5-inch) or $86,000 for an anti-missile variant 155 mm round. LRLAP The development of new ammunition for the AGS under the name Long Range Land Attack Projectile (LRLAP) was one of the major advances offered by the AGS program. The munitions were highly precise, with a circular error probable (CEP) of or less. Lockheed Martin conducted a flight test of the munition in July 2005, reporting a flight distance of . The LRLAP ammunition features separate projectile and propellant portions. Total weight is , including a bursting charge of . The maximum length of the combined munition is , amounting to about 14 calibers. In 2004, the manufacturer stated that the goal for the LRLAP per-round cost was $35,000. Shortly after the was commissioned but prior to weapons system integration, the U.S. Navy moved to cancel the LRLAP due to excessive cost. 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 even though there were no significant performance issues. ==References==