The 5-inch (127 mm)/54-caliber (Mk 45) lightweight gun is a U.S. naval artillery gun mount consisting of a 5 in (127 mm) L54 Mark 19 gun on the Mark 45 mount.[1] It was designed and built by United Defense, a company later acquired by BAE Systems Land & Armaments, which continued manufacture.
The latest 62-calibre-long version consists of a longer-barrel L62 Mark 36 gun fitted on the same Mark 45 mount.[1] The gun is designed for use against surface warships, anti-aircraft and shore bombardment to support amphibious operations.[1] The gun mount features an automatic loader with a capacity of 20 rounds. These can be fired under full automatic control, taking a little over a minute to exhaust those rounds at maximum fire rate. For sustained use, the gun mount would be occupied by a six-person crew (gun captain, panel operator, and four ammunition loaders) below deck to keep the gun continuously supplied with ammunition.
Used mechanical fuze setter. Two-piece rifled construction, with replaceable liner
Mod 1
Electronic fuze setter replaces the mechanical one. Made with a unitary construction barrel, which has a life span approximately twice that of the Mark 42 gun.
Mod 2
Export version of Mod 1, but now used in the U.S. Navy
Mod 3
Mod 2 gun with a new control system; never put into production
Mod 4
Receives a longer 62-caliber barrel (versus Mod 1 and 2's 54 caliber) for more complete propellant combustion and higher velocity[6] and thus more utility for land attack. Was designed to use the Mark 171 Extended Range Guided Munition (ERGM), which was canceled. The Mk 45 mod 4 uses a modified flat-panel gun turret, designed to reduce its radar signature.
In sustained firing operations (Mode III), the gun is operated by a six-person crew: a gun captain, a panel operator, and four ammunition loaders, all located below decks. In fully automatic non-sustained firing operations (Mode IV), 20 rounds can be fired without any personnel inside the mount, using an autoloader.
This section needs to be updated. Please help update this article to reflect recent events or newly available information.(April 2022)
On 9 May 2014, the U.S. Navy released a request for information (RFI) for a guided 5-inch (127 mm) round that could be fired from Mark 45 guns on Navy destroyers and cruisers. This RFI came six years after the cancelation of the RaytheonExtended Range Guided Munition. The shell must have at least double the range of unguided shells for missions including Naval Surface Fire Support (NSFS)/Land Attack, and increasing anti-surface warfare (ASuW) capabilities against fast attack craft (FAC) and fast inshore attack craft (FIAC); the main purpose is to destroy incoming small boats at a greater range with a proximity fuseairburst blast fragmentation warhead to spray shrapnel over swarms.
Expected submissions include the BAE Systems Multi Service–Standard Guided Projectile (MS-SGP), Raytheon Excalibur N5, and OTO Melara Vulcano guided long-range projectile.[7][8]
Naval Sea Systems Command is also looking to fire a version of the hyper-velocity projectile (HVP) developed for Navy electromagnetic railguns from conventional 5-inch deck guns. Using the HVP could give existing destroyers and cruisers better ability to engage land, air, and missile threats and allow more time to refine the railgun. The HVP would be a cheaper solution to intercepting incoming missiles than a missile interceptor costing hundreds of thousands of dollars. Converting the HVP to fire from conventional guns was not a program of record as of 2015[update].[9] HVP shells fired from 5-inch deck guns would travel at Mach 3, half the speed of a railgun but twice the speed of conventional rounds.[10] The rounds would be more expensive than unguided shells but cheaper than missile interceptors, and engage air and missile targets out to 10–30 nautical miles (12–35 mi; 19–56 km).[11] During 2018 RIMPAC exercises, the USS Dewey (DDG-105) fired 20 HVPs from a standard Mk 45 deck gun; an HVP shell could cost US$75,000-$100,000, compared to $1-$2 million for missiles.[12]
The HVP was renamed to the Gun-Launched Guided Projectile (GLGP) for the Electromagnetic Railgun project.[13] In 2022, the United States Department of the Navy terminated the GLGP Research and Development effort.[14][15]
Operators
Map with 5-inch/54-caliber Mark 45 operators in blue Mod 2 gun aboard Australian Anzac-class frigate HMAS AruntaLoading a 70-pound (32 kg) 5-inch round in the below-deck gun mount
Indian Navy: The mod 4 variant was previously planned to be deployed on 7 Nilgiri-class frigate and 4 Visakhapatnam-class destroyer. The procurement of 13 guns was cleared by the Indian Ministry of Defence on 27 April 2018. Of the guns, 11 would be deployed on the above-mentioned ships while the rest of 2 would be in INS Dronacharya missile and gunnery school, and INS Valsura electrical and weapons engineering school.[18] The US Defense Security Cooperation Agency cleared under the Foreign Military Sales for the same deal in 2019. The deal would be worth over $1 billion.[19] However, by 2021, India moved on to the development of an indigenous gun of similar calibre due to cost and logistics factor. Till the completion of the development, the 11 destroyers and frigates would be fitted with already operational OTO Melara 76 mmnaval gun. The 13 gun deal for the Indian Navy did not go through.[20]
See also
Extended Range Guided Munition: long range (~60 nautical miles (110 km; 69 mi)) precision guided projectile program by Raytheon for the Mark 45 gun, canceled in 2008
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