Naval Systems

MK 110 57 mm Gun

Also known as
  • 57mm MK 110 Gun Mount
  • 57 mm MK 110 Gun Mount
  • MK110
  • Bofors 57Mk3
  • Bofors 57 Mk3
  • 57 mm Mk 110 Mod 0
  • Mk 110 Mod 0 Naval Gun System

The MK 110 57 mm Gun is the U.S. designation for BAE Systems' Bofors 57 Mk3 naval gun, a fully automatic 57 mm / 70-caliber mount assembled in Louisville, Kentucky for U.S. service. U.S. Navy, Coast Guard, and BAE Systems sources place the gun on Navy Littoral Combat Ships, including both Freedom and Independence variants, and on Coast Guard National Security Cutters; BAE also describes immediate ammunition-type switching and six-mode programmable 57 mm Mk 295 Mod 0 / Bofors 3P ammunition for air, surface, and shore targets.

MK 110 57 mm Gun, 57 mm naval gun, Naval Systems
Image source: 210709-N-RL695-1119
Profile / Specs

Specifications

Caliber
57 mm
Rate of fire
220 rounds per minute
Range
17,000 m (9.1 nautical miles)
Ready rounds
120
Barrel length
57 mm / 70 calibers
Muzzle velocity
1,035 m/s
Elevation
-10 degrees to +77 degrees
Gun weight
About 6,800-7,000 kg without ammunition, depending on datasheet
System weight
About 14,000 kg with 1,000 rounds onboard in the Bofors 57 Mk3 datasheet
Ammunition
57 mm Mk 295 Mod 0 / Bofors 3P six-mode programmable ammunition
3P round weight
6.1 kg complete 57 mm round
Fire control
Remote operation through a fire-control system, with local backup control
Platform fit
U.S. Navy LCS variants and USCG WMSL / National Security Cutter class ships
System Design Notes
Control

The Navy describes normal remote operation from the ship fire-control system, with local gun-mount control as a backup.

Accuracy aids

BAE's Bofors 57 Mk3 datasheet identifies a muzzle-velocity radar that supports accuracy and helps the gun make use of 3P ammunition.

Integration

BAE's Mk 110 datasheet describes a compact mount needing limited deck penetration and hull integration on ships of about 150 tons or more.

Variants

This record covers the U.S. MK 110 Mod 0 designation for the Bofors 57 Mk3 naval gun rather than the older 57 mm SAK Mk1/Mk2 family.

VariantConfigurationDesignation notes
Bofors 57 Mk3International designation

BAE presents the 57 mm Mk110 as internationally known as the Bofors 57 Mk3, while the U.S. Navy describes the MK 110 as the 57 mm Mk3 developed by BAE Bofors in Sweden.

Sources: 57mm Naval Gun System - BAE Systems, MK 110 57 mm Gun

MK 110 Mod 0U.S. Navy and Coast Guard designation

The Navy fact file identifies the MK 110 Mod 0 as the U.S. service gun assembled at BAE Systems' Louisville facility.

Sources: MK 110 57 mm Gun, 57mm Mk 110 Mod 0 Naval Gun System Datasheet

Ship Platforms

U.S. and manufacturer sources identify the MK 110 as the 57 mm gun fit for Littoral Combat Ships and Coast Guard National Security Cutters.

Firing weaponWeapon typeFiring evidence
Freedom-class Littoral Combat Ship, Freedom-variant littoral combat ship, Naval SystemsFreedom-class Littoral Combat ShipFreedom-variant littoral combat ship

The Navy fact file lists one MK 110 mount per LCS, the LCS fact file identifies Freedom as one of the two LCS variants, and Navy photo coverage documents a 57 mm MK 110 aboard the Freedom-variant USS Sioux City.

Sources: MK 110 57 mm Gun, Littoral Combat Ship Class - LCS, 210709-N-RL695-1119

Multi-Mission Surface Combatant (MMSC), Multi-mission surface combatant / frigate, Naval SystemsMulti-Mission Surface Combatant (MMSC)Freedom-variant export surface combatant

Lockheed Martin describes the MMSC integrated combat system as leveraging the domestic LCS integration of the 57 mm Mk110 deck gun.

Sources: Multi-Mission Surface Combatant (MMSC) - Lockheed Martin

Ammunition And Fire Control

BAE describes the Mk 110 / Bofors 57 Mk3 as a gun-and-ammunition system: the mount can switch between ammunition types, while 57 mm Mk 295 Mod 0 / Bofors 3P rounds are programmed immediately before firing.

FeatureSystem detailReader context
Ready ammunitionThe automatic loader holds 120 ready-to-fire rounds, and the Bofors 57 Mk3 datasheet says the loading system is split into two sections for rapid ammunition-type changes.The gun is built around rapid target changes rather than a single-purpose naval-fire role.
3P / Mk295 roundThe 57 mm 3P datasheet lists a 6.1 kg complete round and describes programmable, pre-fragmented, proximity-fuzed ammunition with PBX explosive fill.In U.S. service BAE's Mk 110 datasheet identifies this as 57 mm Mk 295 Mod 0 ammunition.
Function modesBAE lists six programmable modes: gated proximity, gated proximity with impact priority, time, impact, armor piercing, and default proximity.The round is meant to let one ammunition family cover air-defense, surface, armored surface, and shore-target engagements.
Programming pathBAE says each 3P fuze is programmed by a proximity fuze programmer using fire-control-computer data immediately before firing.The programmable effect depends on the compatible gun, fire-control system, and fuze-setting path.

Sources: 57mm Mk 110 Mod 0 Naval Gun System Datasheet; Bofors 57 Mk3 Naval Gun System Datasheet; 57mm 3P Fuzed Mk295 Ammo Datasheet.

Timeline

MK 110 57 mm Gun Key Events

  1. Current 57 mm Mk3 version designed

    The U.S. Navy fact file says the current version of the gun was designed in 1995 as part of the BAE Bofors 57 mm Mk3 line.

    Sources: MK 110 57 mm Gun

  2. Swedish service begins

    The Navy fact file says the 57 mm Mk3 entered Swedish service in 2000 before U.S. shipboard adoption.

    Sources: MK 110 57 mm Gun

  3. U.S. service adoption

    The Navy fact file gives 2008 as the deployed date for MK 110 service in both Littoral Combat Ship and Coast Guard National Security Cutter classes.

    Sources: MK 110 57 mm Gun

  4. BAE reports 50th U.S. delivery milestone

    BAE said it would deliver the 50th Mk 110 system to U.S. naval forces and was under contract for 58 systems across LCS variants, National Security Cutter, Offshore Patrol Cutter, and Constellation-class frigate programs.

    Sources: BAE Systems to Deliver 50th Mk 110 Gun for U.S. Naval Operations

  5. Current BAE datasheets describe 3P integration

    BAE's current public datasheets describe the Mk 110 / Bofors 57 Mk3 as a 57 mm gun able to switch immediately between ammunition types and use six-mode programmable 57 mm Mk 295 Mod 0 / Bofors 3P rounds.

    Sources: 57mm Mk 110 Mod 0 Naval Gun System Datasheet, Bofors 57 Mk3 Naval Gun System Datasheet, 57mm 3P Fuzed Mk295 Ammo Datasheet

Media

MK 110 57 mm Gun Videos

MK 110 57 mm Gun Images

MK 110 57 mm Gun, 57 mm naval gun, Naval Systems - view 1
Source: 210512-N-RL695-1411
MK 110 57 mm Gun, 57 mm naval gun, Naval Systems - view 2
Source: 210512-N-RL695-1387
MK 110 57 mm Gun, 57 mm naval gun, Naval Systems - view 3
Source: 210709-N-RL695-1119
Related Weapon Systems
Bofors 40 mm L/70, 40 mm towed anti-aircraft autocannon, Air DefenseAir DefenseBofors 40 mm L/7040 mm towed anti-aircraft autocannonThe Bofors 40 mm L/70 is a Swedish postwar anti-aircraft autocannon developed by AB Bofors as a higher-velocity, faster-firing successor to the wartime 40 mm L/60 family. Its towed and naval variants remained in service through upgrades, with source-backed modern use including Lithuanian-supplied guns in Ukrainian air defense and Indian upgraded L/70 guns used as a short-range counter-drone layer during the 2025 India-Pakistan Conflict.
120mm TAK-120, Single 120 mm/46 dual-purpose naval automatic gun turret, Naval SystemsNaval Systems120mm TAK-120Single 120 mm/46 dual-purpose naval automatic gun turretThe 120mm TAK-120 is a Swedish Bofors single-gun naval turret that adapted the linked FAK-120/Lvakan 4501 automatic field-gun line for fast attack craft and small corvettes. NavWeaps and WeaponSystems.net describe it as a water-cooled, automatically loaded dual-purpose gun with Finnish Turunmaa/Pohjanmaa and Indonesian Fatahillah-class service, but no source reviewed directly ties the turret to a cataloged armed conflict.

Sources

MK 110 57 mm GunPublisher: U.S. Navy | Note: Supports the MK 110's 57 mm caliber, 220 rounds per minute rate of fire, 17,000 meter / 9.1 nautical mile range, 120-round magazine, 1995 design date, 2000 Swedish introduction, 2008 U.S. service, BAE Bofors background, and all-LCS / USCG WMSL platform fit with one mount per ship. | Accessed: 2026-07-04Contracts For Dec. 2, 2015 - Department of WarPublisher: U.S. Department of Defense | Note: Supports the 2015 award for one MK 110 Mod 0 gun weapon system and the contract value used for the MK 110 unit cost. | Accessed: 2026-07-04Littoral Combat Ship Class - LCSPublisher: U.S. Navy | Note: Supports the LCS class split into Freedom and Independence variants, with Freedom as the steel monohull variant and Independence as the aluminum trimaran variant. | Accessed: 2026-07-0457mm Naval Gun System - BAE SystemsPublisher: BAE Systems | Note: Supports the Mk110 / Bofors 57Mk3 naming and BAE Systems' statement that the gun is a deck-gun fit for U.S. Coast Guard National Security Cutter and Offshore Patrol Cutter classes and U.S. Navy LCS ships. | Accessed: 2026-07-0457mm Mk 110 Mod 0 Naval Gun System DatasheetPublisher: BAE Systems | Note: Supports Mk 110 Mod 0 specifications including 220 rounds per minute, greater than 9 nautical mile range, 120-round ammunition capacity, elevation/training performance, 6,800 kg complete weight without ammunition, air-cooled barrel life, selected U.S. ship classes, compact integration context, and Mk 295 Mod 0 six-mode programmable ammunition context. | Accessed: 2026-07-04Bofors 57 Mk3 Naval Gun System DatasheetPublisher: BAE Systems | Note: Supports Bofors 57 Mk3 specifications and design context including four rounds per second, immediate ammunition switching, 120 ready rounds, two-section loading system, muzzle velocity radar, 1,035 m/s muzzle velocity, 17,000 m maximum range, 7,000 kg gun weight without ammunition, and about 14,000 kg system weight with 1,000 rounds. | Accessed: 2026-07-0457mm 3P Fuzed Mk295 Ammo DatasheetPublisher: BAE Systems | Note: Supports the 57 mm 3P / Mk295 ammunition details used on the MK 110 page, including 6.1 kg complete-round weight, 675.3 mm length, PBX explosive fill, 1,035 m/s muzzle velocity, six programmable function modes, and immediate pre-firing fuze programming. | Accessed: 2026-07-04BAE Systems to Deliver 50th Mk 110 Gun for U.S. Naval OperationsPublisher: BAE Systems | Note: Supports BAE Systems' January 2022 50th Mk 110 U.S. delivery milestone, Louisville manufacturing context, total 58-system U.S. contract context, and statement that the Mk 110 is under contract for both Navy LCS variants, Coast Guard National Security Cutters, Offshore Patrol Cutters, and the Constellation-class frigate program. | Accessed: 2026-07-04Yard News July/August 2018Publisher: U.S. Coast Guard | Note: Supports Coast Guard Yard overhaul of a MK 110 57 mm gun mount and identifies MK 110 as installed on Navy Littoral Combat Ships and Coast Guard National Security Cutters. | Accessed: 2026-07-04Multi-Mission Surface Combatant (MMSC) - Lockheed MartinPublisher: Lockheed Martin | Note: Supports Lockheed Martin's MMSC relationship claim that the integrated combat system leverages the domestic LCS integration of the 57 mm Mk110 deck gun. | Accessed: 2026-07-04210709-N-RL695-1119Publisher: U.S. Navy | Note: Supports image provenance and the USS Sioux City / MK 110 relationship in July 2021. | Accessed: 2026-07-04210512-N-RL695-1411Publisher: U.S. Navy | Note: Supports image provenance for a second USS Sioux City photo of the MK 110 gun in maintenance context. | Accessed: 2026-07-04210512-N-RL695-1387Publisher: U.S. Navy | Note: Supports image provenance for a third USS Sioux City photo showing the MK 110 mount during maintenance. | Accessed: 2026-07-04USS Billings Fires its 57mm MK 110 GunPublisher: DVIDS | Note: Supports public-domain image provenance for a U.S. Navy photo of USS Billings firing its 57 mm MK 110 gun during a January 2022 live-fire event. | Accessed: 2026-07-04