View source for Advanced Gun System

{{Infobox weapon
| name               = Advanced Gun System
| image              = File:US Navy 090916-N-9999K-003 The Office of Naval Research's Advanced Gun Barrel Technology Program demonstrates a new coating to extend 155-mm barrel life during a test demonstration.jpg
| image_size         = 300px
| caption            = Test firing of Advanced Gun System
| origin             = United States
| type               = [[Naval artillery]]
<!-- Type selection -->
| is_ranged          = yes
| is_bladed          =
| is_explosive       =
| is_artillery       = yes
| is_vehicle         =
| is_missile         =
| is_UK              =
<!-- Service history -->
<!--Never actually in service, since it was never deployed on a ship with ammunition -->
| service            =
| used_by            =
| wars               =
<!-- Production history -->
| designer           = [[BAE Systems Land & Armaments]]
| design_date        = 1996
| manufacturer       = [[BAE Systems Land & Armaments]]
| unit_cost          =
| production_date    = 2010
| number             = 6
| variants           =
<!-- General specifications -->
| spec_label         =
| weight             = {{convert|104|ST|t LT|lk=on}}
| length             =
| part_length        = {{convert|9.61|m|abbr=on}}
| width              =
| height             =
| diameter           =
| crew               =
<!-- Ranged weapon specifications -->
| cartridge          =
| cartridge_weight   =
| caliber            = 155 mm (6.1 inch)
| barrels            =
| action             =
| velocity           =
| max_range          =
| feed               =
| sights             =
<!-- Artillery specifications -->
| breech             =
| recoil             =
| carriage           =
| elevation          = +70 / −5 degrees
| traverse           =
| rate               = 10 rounds per minute (rpm)
| range              = {{convert|83|nmi|km|-1|abbr=on}} with [[Long Range Land Attack Projectile]] (LRLAP)
}}

The '''Advanced Gun System''' ('''AGS''') is a [[naval artillery]] system developed and produced by [[BAE Systems Land & Armaments|BAE Systems Armaments & Services]] for the [[Zumwalt-class destroyer|''Zumwalt''-class destroyer]] of the [[United States Navy]]. Designated the '''155&nbsp;mm/62 (6.1-inch) Mark 51 Advanced Gun System (AGS)''',<ref name=mark51>[http://www.navweaps.com/Weapons/WNUS_61-62_ags.php 155&nbsp;mm/62 (6.1") Mark 51 Advanced Gun System (AGS)], NavWeaps.com, 26 February 2017</ref> it was designed to provide long-range [[naval gunfire support]] against shore-based targets. A total of six of the systems were installed, two on each of the three ''Zumwalt''-class ships. The Navy has no plans for additional ''Zumwalt''-class ships,<ref>"Root Cause Analyses of Nunn-McCurdy Breaches -- Zumwalt-Class Destroyer, Joint Strike Fighter, Longbow Apache, and Wideband Global Satellite," Rand Corporation (2011); see Vol. 1, Ch. 3 via http://www.rand.org/pubs/monographs/MG1171z1.html</ref> and no plans to deploy AGS on any other ship. AGS can only use ammunition designed specifically for the system. Only one ammunition type was designed, and the Navy halted its procurement in November 2016 due to cost ($800,000 to $1,000,000 per round), so the AGS has no ammunition and cannot be used.<ref name="defensenews6nov16" /><ref name="nonewammo" /><ref name="mark51" /> The Navy planned to remove the AGS from the ships starting in 2023.<ref name="remove"/>

== History ==
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&nbsp;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 [[Indian Head Naval Surface Warfare Center|Naval Ordnance Station Indian Head]] tested an {{convert|11|in|abbr=on}} sub-caliber saboted long-range round<ref name="Van Dam">{{Cite thesis |first=L. Bruce |last=Van Dam|title =Does the Past Have a Place in the Future? The Utility of Battleships into the Twenty-First Century |url=http://apps.dtic.mil/dtic/tr/fulltext/u2/a367903.pdf |archive-url=https://web.archive.org/web/20160304054053/http://www.dtic.mil/dtic/tr/fulltext/u2/a367903.pdf |url-status=live |archive-date=4 March 2016 |publisher=US Army Command and General Staff College|place=Fort Leavenworth, Kansas|date=June 4, 1999 |via=[[Defense Technical Information Center]]}}, citing a letter from Major Tracy Ralphs to Senator John Warner on February 25, 1999</ref> in a stretched [[16"/45 caliber Mark 6 gun]] in 1967.<ref name="navweaps">{{cite web |url=http://www.navweaps.com/Weapons/WNUS_16-50_mk7.htm |title=United States of America 16"/50 (40.6 cm) Mark 7 |publisher=Tony DiGiulian, navweaps.com |date=August 9, 2008}}</ref> The Advanced Gun Weapon System Technology Program (AGWSTP) evaluated a similar projectile with longer range in the 1980s.<ref name="Van Dam" /> After the last battleship,  [[USS Missouri (BB-63)|USS ''Missouri'' (BB-63)]], was decommissioned on 31 March 1992, the AGWSTP became a 127&nbsp;mm (5-inch) gun with an intended range of {{convert|180|km|mi|abbr=on}}, which then led to the Vertical Gun for Advanced Ships (VGAS). The original [[DD-21]] (1994 precursor to the ''Zumwalt''-class design) was designed around this "vertical gun", but the project encountered serious technology and cost problems.

Originally designed for mounting as a vertical gun adapted from the VGAS design, this {{convert|155|mm|abbr=on}} AGS was then designed and produced for mounting within a more conventional turret arrangement. The AGS was designed to deliver 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 munition]]s; the [[gun turret|turret]] mounting allows the use of unguided munitions as well if any are developed for it. Even though the {{convert|155|mm|abbr=on}} caliber is the standard for both the US Army and NATO land artillery systems, the AGS is not designed to use the same standard munitions as other {{convert|155|mm|abbr=on}} artillery. This means that each type of munition must be designed and manufactured specifically for the AGS.<ref name="defensenews6nov16" />

[[Long Range Land Attack Projectile]] (LRLAP) ammunition for AGS was to be a major advance. LRLAP featured separate projectile and propellant portions and was to be highly precise, with a [[circular error probable]] (CEP) of {{convert|50|m|abbr=on}} or less. [[Lockheed Martin]]'s flight test of the munition in July 2005 had a reported a flight distance of {{convert|59|nmi}}. However, LRLAP procurement was cancelled in 2016<ref name="defensenews6nov16">[http://www.defensenews.com/articles/new-warships-big-guns-have-no-bullets New Warship’s Big Guns Have No Bullets] - Defensenews.com,  November 6, 2016</ref><ref name="USNI071116">[https://news.usni.org/2016/11/07/navy-planning-not-buying-lrlap-rounds Navy Planning on Not Buying More LRLAP Rounds for Zumwalt Class] - News.USNI.org, November 7, 2016</ref> and the navy had no plan to replace it.<ref name="nonewammo">[https://www.defensenews.com/digital-show-dailies/surface-navy-association/2018/01/11/navy-has-no-plan-to-introduce-new-ammo-for-ddg-1000 Navy has no plan to introduce new ammo for DDG-1000] Defense News, January 11, 2018</ref> By early 2021, the navy was exploring replacing the AGS on ''Zumwalt''-class ships with modules to carry [[hypersonic]] missiles.<ref>[https://www.navytimes.com/naval/2021/03/25/what-should-become-of-the-zumwalt-class-the-us-navy-has-some-big-ideas/ What should become of the Zumwalt class? The US Navy has some big ideas.] ''[[Navy Times]]''. March 25, 2021.</ref> In March 2022, it was announced that both AGS would be removed from ''Zumwalt''-class destroyers to enable installation of tubes to accommodate [[Long-Range Hypersonic Weapon|Common-Hypersonic Glide Body]] missiles. The switch was scheduled to begin in late 2023 as the ships undergo maintenance periods.<ref name="remove">{{cite web|last=LaGrone|first=Sam|title=Latest Zumwalt Hypersonic Missile Installation Plan Calls For Removing Gun Mounts|date=March 16, 2022|access-date= May 8, 2022|url=https://news.usni.org/2022/03/16/latest-zumwalt-hypersonic-missile-installation-plan-calls-for-removing-gun-mounts|work= USNI News}}</ref>

AGS was developed and produced by [[BAE Systems Land & Armaments|BAE Systems Armaments Systems]] (formerly [[United Defense]]) for the [[Zumwalt-class destroyer|''Zumwalt''-class destroyer]] of the [[United States Navy]]. The first magazine was delivered to the U.S. Navy on May 25, 2010.<ref name="BAE Systems">{{cite web |title=BAE Systems Delivers First Piece of Production Hardware for U.S. Navy's Advanced Gun System |publisher=BAE Systems |year=2010 |url=http://www.baesystems.com/product/BAES_020037/advanced-gun-system-ags |accessdate=February 4, 2013}}</ref>

== Description ==
The AGS uses the same 155&nbsp;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.<ref name=LaGrone/> The gun barrel is 62 [[caliber (artillery)|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 mounted in a turret specifically designed for the [[Zumwalt-class destroyer|''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 and hidden from radar when not firing.

A primary advantage of the AGS over the existing 127&nbsp;mm [[5-54 Mark 45|Mark 45 5-inch gun]] which equips most major surface combatants of the US Navy was to be its increased capability for supporting ground forces and striking land targets.  With a 10-round-per-minute capacity, it would have had the ability to deliver the firepower of a battery of six 155&nbsp;mm [[M109 howitzer|howitzers]].<ref name="DI20140223">{{cite web |last= |first= |url=http://www.defenseindustrydaily.com/next-gen-naval-gunfire-support-the-usas-ags-lrlap-07171/ |title=Next-Gen Naval Gunfire Support: The USA's AGS & LRLAP |website=Defense Industry Daily |date=23 February 2014}}</ref> 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 {{as of|2018|lc=on}} was the LRLAP. LRLAP procurement, however, was canceled and there are no plans to replace it.<ref name="nonewammo"/> Other projectiles were 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.<ref name="Cavas">{{cite web|url=http://www.defensenews.com/articles/new-warships-big-guns-have-no-bullets|title=New Warship's Big Guns Have No Bullets|last=Cavas|first=Christopher P.|website=DefenseNews|date=2016-11-06}}</ref><ref name="USNI071116" /> It could cost up to $250&nbsp;million in engineering costs to modify all six guns on the three ships to accept a new round.<ref>[https://news.usni.org/2016/12/13/raytheon-excalibur-round-set-replace-lrlap-zumwalts Raytheon Excalibur Round Set to Replace LRLAP on Zumwalts] - News.USNI.org, 13 December 2016</ref>

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.<ref name=LaGrone>{{cite news |last=LaGrone |first=Sam |date=January 11, 2018 |title=No New Round Planned For Zumwalt Destroyer Gun System; Navy Monitoring Industry |url=https://news.usni.org/2018/01/11/no-new-round-planned-zumwalt-destroyer-gun-system-navy-monitoring-industry |work=USNI News |publisher=US Naval Institute |access-date=March 2, 2018 }}</ref> In particular he noted that the BAE Hypervelocity Projectile testing, a cross-service 127&nbsp;mm (5-inch) naval and 155&nbsp;mm land, low-drag self-guided Mach 7-capable round originally intended for [[railgun]]s, 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&nbsp;mm (5-inch) or $86,000 for an anti-missile variant 155&nbsp;mm round.<ref>[https://breakingdefense.com/2018/01/86000-5600-mph-hyper-velocity-missile-defense/ $86,000 + 5,600 MPH = Hyper Velocity Missile Defense] Breaking Defense, January 26, 2018</ref>

===LRLAP===
{{main|Long Range Land Attack Projectile}}
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 {{convert|50|m|abbr=on}} or less. [[Lockheed Martin]] conducted a flight test of the munition in July 2005, reporting a flight distance of {{convert|59|nmi}}. The LRLAP ammunition features separate projectile and propellant portions. Total weight is {{convert|225|lb}}, including a bursting charge of {{convert|24|lb|abbr=on}}. The maximum length of the combined munition is {{convert|88|in|cm|abbr=on}}, amounting to about 14 calibers.

In 2004, the manufacturer stated that the goal for the LRLAP per-round cost was $35,000.<ref>{{cite web|url=http://www.navweaps.com/Weapons/WNUS_61-62_ags.php|title=155&nbsp;mm/62 (6.1") Mark 51 Advanced Gun System (AGS)|publisher=Navweps}}</ref> Shortly after the {{USS|Zumwalt|DDG-1000}} was commissioned but prior to weapons system integration,<ref name="special commissioning">{{cite web
 |url=https://seapowermagazine.org/geurts-third-zumwalt-ddg-will-be-commissioned-after-combat-systems-activation/
 |title=Geurts: Third Zumwalt DDG Will Be Commissioned After Combat Systems Activation
 |last=Burgess
 |first=Richard R.
 |date=April 28, 2020
 |website=
 |publisher=Seapower Magazine
 |access-date=February 12, 2021
}}</ref> 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&nbsp;million. This made the system untenable even though there were no significant performance issues.<ref name="Cavas" />

==References==
{{Reflist}}

==External links==
* {{youtube|pg1uHRVx8-I|AGS employment in asymmetric warfare simulation scenario}}
* {{youtube|ilwIhIwf5yI|AGS non-combatant evacuation simulation scenario}}
{{Use dmy dates|date=June 2017}}

[[Category:155&nbsp;mm artillery]]
[[Category:Naval guns of the United States]]
[[Category:BAE Systems weapons systems]]
[[Category:Military equipment introduced in the 2010s]]
[[Category:United Defense]]