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5-inch/54-caliber Mark 45 gun

(Redirected from 5"/62 caliber Mark 45 gun)

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] The later 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 which can be fired under full automatic control, taking a little over a minute 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.

Mark 45 5-inch/54 and 62-caliber lightweight gun
5-inch/62-caliber Mark 45 Mod 4, in flat-panel gun turret, test firing on USS Forrest Sherman
TypeNaval gun
Place of originUnited States
Service history
In service1971–present
Used bySee Operators
Production history
Designed1968[1]
ManufacturerUnited Defense[1] (now BAE Systems Land & Armaments)
Produced1971[1]
Specifications (Mod 2)
Mass21,691 kg (47,820.5 lb)[1]
Length8.992 m (29 ft 6.0 in)[3]
Barrel length6.858 m (22 ft 6.0 in)[3]
Rifling: 5.82 m (19 ft 1 in)[3]
  • Mod 4: 7.874 m (25 ft 10.0 in)
Shell127 × 835 mm .R
Conventional: 31.75 kg (70.0 lb)[1]
Caliber54 caliber (Mod 1 and Mod 2) 62 caliber (Mod 4)
Elevation
  • −15° to +65°[3]
  • Max. elevation rate: 20°/s[3]
Traverse
  • ±170° from centerline[3]
  • Max. traversing rate: 30°/s[3]
Rate of fire16–20 rounds per minute automatic[4]
Muzzle velocity
  • 2,500 ft/s (760 m/s)[1]
  • 1,500 ft/s (460 m/s) reduced charge for defilade fire or illumination rounds
Effective firing range13 nmi (24.1 km)[4] or 20 nmi (37.0 km) (Mod 4)[5]

It was designed and built by United Defense, a company later acquired by BAE Systems Land & Armaments, which continued manufacture.

History

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Development started in the 1960s as a replacement for the 5-inch (127 mm)/54-caliber Mark 42 gun system that had debuted in 1953, with a new, lighter, and easier-to-maintain gun mounting. The United States Navy uses the Mark 45 with either the Mk 86 Gun Fire Control System or the Mk 34 Gun Weapon System.

Since before World War II, 5 inches (127 mm) has been the standard gun caliber for U.S. Naval ships. Its rate of fire is lower than the British 4.5 in (114 mm) gun, but it fires a heavier 5-inch (127 mm) shell which carries a larger burst charge that increases its effectiveness against aircraft.

Variants

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Mod 2
Mod 4

Mod 0

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Used mechanical fuze setter. Two-piece rifled construction, with replaceable liner.

Mod 1

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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

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Export version of Mod 1, but now used in the U.S. Navy.

Mod 3

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Mod 2 gun with a new control system. Never put into production.

Mod 4

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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. 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.

In 2024–2025, U.S. Navy destroyers in the Red Sea increasingly employed the Mk 45 gun to defend themselves and merchants against one-way attack drones, launched by the Houthi rebels from Yemen during the Red Sea crisis.[7]

Ammunition

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Mark 68 HE-CVT

  • Weight – 68.5 lb (31.1 kg)
  • Projectile Length – 26.1 in (66.3 cm)
  • Used only with Mods 0–2

Mark 80 HE-PD

  • Weight – 67.6 lb (30.7 kg)
  • Projectile Length – 26 in (66 cm)
  • Explosive filler: 8.2 lb (3.7 kg) Composition B[8]

Mark 91 Illum-MT

  • Weight – 63.9 lb (29.0 kg)
  • Projectile Length – 26.1 in (66.3 cm)

Mark 116 HE-VT

  • Weight – 69.7 lb (31.6 kg)
  • Projectile Length – 26 in (66 cm)

Mark 127 HE-CVT

  • Weight – 68.6 lb (31.1 kg)
  • Projectile Length – 26 in (66 cm)

Mark 156 HE-IR

  • Weight – 69.0 lb (31.3 kg)
  • Projectile Length – 26 in (66 cm)

Mark 172 HE-ICM (Cargo Round)

  • Projectile Length – 26 in (66 cm)
  • Used only with Mod 4[2][3]

Guided shell

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In May 2014, the U.S. Navy issued a request for information (RFI) for a guided 5-inch (127 mm) projectile capable of being fired from Mark 45 guns aboard Navy destroyers and cruisers. This RFI followed the cancellation of the Raytheon Extended Range Guided Munition program approximately six years earlier. The proposed munition was required to achieve at least twice the range of conventional unguided shells and support missions including Naval Surface Fire Support (NSFS)/land attack and enhanced anti-surface warfare (ASuW) against fast attack craft (FAC) and fast inshore attack craft (FIAC). A primary objective was to defeat swarming small-boat threats at extended ranges using a proximity fuse airburst fragmentation warhead capable of dispersing shrapnel over a wide area.

Submissions included the BAE Systems Multi Service–Standard Guided Projectile (MS-SGP), Raytheon Excalibur N5, and the OTO Melara Vulcano guided long-range projectile.[9][10]

By 2015, Naval Sea Systems Command was investigating the feasibility of firing a version of the hyper-velocity projectile (HVP), originally developed for Navy electromagnetic railgun systems, from conventional 5-inch deck guns. Employing HVP from existing platforms was intended to enhance engagement capability against land, air, and missile threats while allowing additional time for railgun development. The HVP concept also offered a potentially lower-cost alternative to missile interceptors, which can cost hundreds of thousands to millions of dollars per engagement. As of 2015, adapting HVP for conventional guns was not a formal program of record.[11]

When fired from conventional 5-inch guns, HVP rounds were expected to achieve velocities of approximately Mach 3—about half the velocity attained when fired from a railgun, but roughly twice that of standard naval gun projectiles.[12] Although more expensive than unguided shells, HVPs were projected to be significantly less costly than missile interceptors, while providing engagement ranges against air and missile threats of approximately 10–30 nautical miles (12–35 mi; 19–56 km).[13]

During the 2018 RIMPAC exercises, USS Dewey (DDG-105) fired 20 HVP rounds from a standard Mk 45 deck gun. The 2019 unit cost estimates ranged from US$75,000 to $100,000 per round, compared to approximately $1–2 million per missile interceptor.[14]

Within the electromagnetic railgun program, the HVP was later redesignated as the Gun-Launched Guided Projectile (GLGP).[15] In 2022, the U.S. Department of the Navy terminated GLGP research and development.[16][17]

In 2024, the Navy resumed developmental testing of the Hypervelocity Projectile, manufactured by BAE Systems USA.[18] The HVP is a saboted projectile also being developed under a U.S. Army contract. While the Army variant uses a larger 155 mm sabot, the projectile body is common to both services; the Navy version employs a smaller 5-inch (127 mm) sabot compatible with Mk 45 guns.[19]

Operators

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A map of 5-inch/54-caliber Mark 45 operators in blue
A Mod 2 gun aboard the Australian Anzac-class frigate HMAS Arunta
Loading a 70-pound (32 kg) 5-inch round in the below-deck gun mount

Current operators

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 Australia
 Denmark
 Greece
 Japan
 South Korea
 New Zealand
 Spain
 Taiwan
 Thailand
 Turkey
 United States

Future operators

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Cancelled deals

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 India

  • Indian Navy: The mod 4 variant was 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 in April 2018. Of the guns, 11 would be deployed on the above-mentioned ships while 2 would be in the INS Dronacharya missile and gunnery school, and the INS Valsura electrical and weapons engineering school.[23] 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.[24] In 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 mm naval gun. The 13 gun deal for the Indian Navy did not go through.[25]

See also

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Weapons of comparable role, performance and era

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References

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Notes

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  1. 1 2 3 4 5 6 7 8 9 10 11 12 Norman Polmar, pp. 492–493
  2. 1 2 "United States of America 5"/54 (12.7 cm) Mark 45 Mod 4". NavWeaps.Com. 18 April 2010. Archived from the original on 2 January 2015. Retrieved 24 October 2010.
  3. 1 2 3 4 5 6 7 8 "United States of America 5"/54 (12.7 cm) Mark 45 Mods 0–2". NavWeaps.Com. 18 September 2007. Archived from the original on 3 January 2015. Retrieved 24 October 2010.
  4. 1 2 3 4 5 "The US Navy Fact File: 5-inch Mark 45 54-caliber lightweight gun". United States Navy. 20 February 2009. Archived from the original on 5 December 2010. Retrieved 24 October 2010.
  5. ↑ "Mk 45 Mod 4 Naval Gun System". BAE Systems. Retrieved 15 March 2020.
  6. ↑ "5-inch 62-Caliber Mk 45 Mod 4 Naval Gun System" (PDF). Brochure. BAE Systems. Archived from the original (PDF) on 25 April 2012. Retrieved 5 October 2011.
  7. ↑ "Crew of USS Stockdale Shot Down Houthi Drones with 5-Inch Gun, Says Admiral". 30 January 2025.
  8. ↑ Ammunition: Nexter Catalogue 2018.
  9. ↑ Navy Taking a Second Look at A Five-Inch Guided Round Archived 9 June 2014 at the Wayback Machine – News.USNI.org, 3 June 2014
  10. ↑ Navy seeks guided deck-gun shell – Navytimes.com, 4 June 2014
  11. ↑ LaGrone, Sam (2 June 2015). "Updated: Navy Researching Firing Mach 3 Guided Round from Standard Deck Guns". USNI News. Archived from the original on 1 June 2015.
  12. ↑ The Future of the Navy's Electromagnetic Railgun Could Be a Big Step Backwards Archived 16 July 2016 at the Wayback Machine - Popularmechanics.com, 6 June 2016
  13. ↑ Pentagon: New Rounds For Old Guns Could Change Missile Defense for Navy, Army Archived 19 July 2016 at the Wayback Machine - News.USNI.org, 18 July 2016
  14. ↑ Navy Quietly Fires 20 Hyper Velocity Projectiles Through Destroyer's Deckgun Archived 9 January 2019 at the Wayback Machine. USNI News. 8 January 2019.
  15. ↑ "USA 5"/62 (12.7 cm) Mark 45 Mod 4". NavWeaps. 21 December 2022. Retrieved 5 October 2024.
  16. ↑ Seck, Hope (4 June 2021). "It May Be the End of the Line for the Navy's Hypervelocity Projectile". Military.com. Retrieved 5 October 2024.
  17. ↑ "Highlights of the Department of the Navy FY 2022 Budget" (PDF). Secretary of the Navy. p. 12-3. Archived from the original (PDF) on 9 June 2021. Retrieved 5 October 2024.
  18. ↑ "BAE Systems' Hypervelocity Projectile (HVP) at SNA 2025". YouTube. 17 January 2025.
  19. ↑ "Army to sole-source deal for hypervelocity projectiles, drone-killing artillery cannon". 27 December 2024.
  20. ↑ "BAE to install Mk 45 systems for Navy - Australian Defence Magazine".
  21. ↑ Seidel, Jamie (2 July 2018). "Australia's Hunter class Type 26 frigates explained". News.com.au. Archived from the original on 1 March 2019. Retrieved 18 March 2019.
  22. ↑ "Canada reveals updated River-class destroyer design with major combat system changes". Army Recognition. 25 March 2026. Retrieved 25 March 2026.
  23. ↑ "DAC Approves Capital Acquisition Proposals Worth Rs 3,687 Crore". Press Information Bureau. 27 April 2018. Retrieved 18 September 2024.
  24. ↑ Philip, Snehesh Alex (21 November 2019). "Ghost of Finmeccanica behind it, Indian Navy to finally get its big guns as US steps in". ThePrint. Retrieved 18 September 2024.
  25. ↑ Snehesh, Alex Philip. "Navy to scrap plans to procure guns from US, considering 'Make in India' route now". ThePrint. Archived from the original on 2 August 2021.

Bibliography

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