Polish Rosomak vehicles served with the ISAF mission in Afghanistan, and Defence24 identifies a Rosomak with the Hitfist-30P turret on patrol there in March 2010; the Hitfist-30P IFV variant used the 30 mm Bushmaster II Mk44 cannon.
Support Equipment
Mk44 Bushmaster II
Also known as
- Mk44
- Mk44 Bushmaster
- Mk44S
- Mk44S Stretch
- Mk44 Stretch
- XM813
- XM813 Bushmaster
- GAU-23
- GAU-23/A
- Mk44 30mm Bushmaster Chain Gun
- 30 mm Mk44 Bushmaster II
- Bushmaster II
The Mk44 Bushmaster II is a Northrop Grumman 30 mm externally powered chain gun used as the gun element in ground vehicles, naval mounts, and aircraft gun installations. Official material ties the base Mk44 to 30 x 173 mm ammunition and Mk310 programmable air-burst rounds, while the Mk44S, XM813, and GAU-23/A branches show how the family was adapted for 40 mm growth, Stryker Dragoon integration, and AC-130-class aircraft use.
Role in Conflicts
- Side
- Ukraine
Ukraine fields Polish Rosomak combat variants with Hitfist-30P turrets and Bushmaster cannon armament, and the UK announced Terrahawk Paladin air-defense systems for Ukraine; Terrahawk reporting identifies the system's 30 mm gun as the Mk44 Bushmaster II.
Role detailsProfile / Specs
Profile
- Origin
- United States
- Built by
- Northrop Grumman
- Type
- 30 mm chain-gun automatic cannon
- Service note
- Modern Bushmaster chain-gun family
- Designer
- Alliant Techsystems / Northrop Grumman
- Produced
- In current production as a commercial-off-the-shelf Bushmaster family cannon
Specifications
- Caliber
- 30 x 173 mm; compatible with 30 x 170 mm Rarden and KCB according to the Northrop Grumman Mk44 datasheet
- Operating principle
- Externally powered Bushmaster chain gun with positive round control
- Feed system
- Dual feed
- Rate of fire
- Single shot, burst, or full automatic at 200 shots per minute
- Total weight
- 344 lb / 156 kg for receiver, feeder, and barrel in the Northrop Grumman datasheet
- Power requirement
- 1.0 hp at 24 VDC
- Mk44S growth path
- 363 lb / 165 kg 30/40 mm variant in the Northrop Grumman datasheet; field-upgradable from 30 x 173 mm to 40 mm Super Forty ammunition
- XM813 configuration
- Mk44S-derived 30/40 mm cannon with integral mount, dual recoil system, linkless/closed-bolt Stryker Dragoon configuration, and 1.5 hp at 24 VDC power requirement
- GAU-23 aircraft configuration
- Aircraft version of the Mk44 with dual feed, side ejection, and 450 lb / 204 kg total weight in the Northrop Grumman datasheet
- Ammunition relationship
- 30 x 173 mm Bushmaster-family ammunition, including Mk310 programmable air-burst munition compatibility
Variants
Public Northrop Grumman material distinguishes the base Mk44, the Mk44S Stretch, the XM813 U.S. Army variant, and the GAU-23 aircraft version by ammunition growth path, feed arrangement, and host-system integration.
| Variant | Configuration | Designation notes |
|---|---|---|
| Mk44 | 30 x 173 mm automatic cannon | Northrop Grumman describes the Mk44 as a 30 mm Bushmaster chain gun for ground and naval platforms that can fire Mk310 programmable air-burst munitions. Sources: Northrop Grumman 30x173mm Bushmaster Chain Guns, Northrop Grumman Mk44 Datasheet |
| Mk44S Stretch | 30/40 mm growth variant | Northrop Grumman says the Mk44S fires 30 x 173 mm ammunition, can be field-upgraded for 40 mm Super Forty ammunition, and is offered with link-fed or linkless-feed configurations. Sources: Northrop Grumman 30x173mm Bushmaster Chain Guns, Northrop Grumman Mk44S Datasheet |
| XM813 | U.S. Army Mk44S variant | Northrop Grumman identifies XM813 as a Mk44S variant adopted for the Stryker Dragoon 30 mm Medium Caliber Weapon System program, and DOT&E describes the ICV-D installation as an electrically operated XM-813 main gun in an unmanned MCT-30 weapon system. Sources: Northrop Grumman 30x173mm Bushmaster Chain Guns, Northrop Grumman XM813 Datasheet, DOT&E Stryker ICV-D FY2018 Report |
| GAU-23/A | Aircraft version | Northrop Grumman describes the GAU-23 as the aircraft version of the Mk44 for AC-130J Ghostrider and Marine Corps Harvest Hawk applications; ATK announced U.S. Air Force type classification for AC-130W integration in 2012. Sources: Northrop Grumman 30x173mm Bushmaster Chain Guns, Northrop Grumman GAU-23 Datasheet, ATK GAU-23 Type Classification |
Ammunition Fired
The Mk44 is part of Northrop Grumman's 30 x 173 mm Bushmaster chain-gun family.
| Ammunition | Ammunition type | Firing evidence |
|---|---|---|
 | 30 mm ammunition family | Northrop Grumman describes the Mk44 as firing 30 x 173 mm ammunition and identifies Mk310 programmable air-burst munitions as compatible with the gun. Sources: Northrop Grumman 30x173mm Bushmaster Chain Guns, Northrop Grumman Mk44 Datasheet |
 | 30 mm programmable air-burst round | Northrop Grumman identifies Mk310 programmable air-burst ammunition as compatible with the Mk44 family, and the ammunition brochure describes Mk310 PABM-T as designed for the Bushmaster Mk44 cannon. Sources: Northrop Grumman 30x173mm Bushmaster Chain Guns, Northrop Grumman 30x173mm Full Ammo Suite Brochure |
| 30 mm high-explosive incendiary tracer round | Northrop Grumman lists Mk238 HEI-T/SD as a 30 x 173 mm round used in the Mk44 or any cannon firing 30 x 173 mm ammunition. |
 | 30 mm target-practice tracer round | Northrop Grumman says Mk239 TP-T was developed for ground-vehicle applications that use Mk44 cannons or any cannon firing 30 x 173 mm ammunition. |
 | 30 mm high-explosive incendiary tracer round | Northrop Grumman lists Mk266 HEI-T as a 30 x 173 mm round usable in the Mk44 or any cannon firing 30 x 173 mm ammunition. |
Compatible Mounts And Platforms
The cannon family appears in weapon systems rather than as a standalone battlefield item; public catalog links are limited to existing published platform or mount records.
| Compatible item | Item type | Compatibility evidence |
|---|---|---|
 | 30 mm naval gun system | The U.S. Navy identifies the MK 46 Mod 2 Gun Weapon System as including the Mk 44 Mod 2 30 mm cannon and lists LPD-17, DDG-1000, and LCS class platform fits. Sources: U.S. Navy MK 46 Gun Weapon System |
 | 30 mm naval gun mount | MSI-Defence identifies the SEAHAWK DS A2/DS30M family with Mk44 cannon integration, matching Northrop Grumman's naval-platform framing for the Mk44 family. Sources: MSI-DS SEAHAWK DS A2, Northrop Grumman 30x173mm Bushmaster Chain Guns |
 | 8x8 armored fighting vehicle family | Northrop Grumman identifies XM813 as a Mk44S variant adopted for the Stryker Dragoon 30 mm Medium Caliber Weapon System program, and DVIDS documents 2nd Cavalry Regiment receiving the 30 mm Stryker Dragoon in Germany. Sources: Northrop Grumman 30x173mm Bushmaster Chain Guns, DVIDS 2CR First 30mm Stryker |
 | 8x8 armored personnel carrier and IFV family | Ukraine's Ministry of Defence identifies the Rosomak combat variant with the Hitfist-30P turret, and Defence24 identifies the Hitfist-30P IFV variant's main gun as the 30 mm Bushmaster II Mk44. Sources: Ukraine MOD Rosomak APC Overview, Defence24 Rosomak in Ukraine |
 | Very short-range counter-UAS air-defense system | European Security & Defence described the Terrahawk VSHORAD demonstrator with a Mk44 Bushmaster II cannon, and UK/Ukrainian reporting ties Terrahawk Paladin systems to Ukraine's short-range air-defense effort. Sources: European Security & Defence Terrahawk VSHORAD Details, UK MOD Ukraine Support Package Terrahawk Paladin, Ukrainska Pravda Ukraine Deploys Terrahawk Paladin |
Timeline
Mk44 Bushmaster II Key Events
GAU-23/A type classification announced
ATK announced U.S. Air Force type classification of the GAU-23/A automatic cannon for AC-130W gunship integration.
Sources: ATK GAU-23 Type Classification
Army demonstrates a 30 mm Stryker lethality path
Army reporting described a Stryker-like vehicle with a Kongsberg medium-caliber remote weapon station and a 30 mm weapon system demonstrated at Fort Benning.
Sources: Army Stryker Increased Lethality Demonstration
First 30 mm Stryker Dragoon reaches 2nd Cavalry Regiment
DVIDS reported that 2nd Cavalry Regiment received its first 30 mm Stryker Infantry Carrier Vehicle - Dragoon in Germany, with fielding tied to a 2015 urgent operational needs statement.
Sources: DVIDS 2CR First 30mm Stryker
DOT&E describes the XM-813 ICV-D installation
DOT&E's FY2018 Stryker ICV-D report described the XM-813 30 mm main gun, electric-motor operation, gravity-fed ammunition boxes, and unmanned MCT-30 weapon-system integration.
Sources: DOT&E Stryker ICV-D FY2018 Report
First Stryker MCWS test vehicle delivered
Oshkosh Defense reported delivery of the first Stryker Double-V Hull Infantry Carrier Vehicle upgraded with the 30 mm Medium Caliber Weapon System for Army production verification testing.
Sources: Oshkosh Defense First Stryker MCWS Delivery
NAVSEA reports MK 38 Mod 4 with MK 44 core
NAVSEA reported that the MK 38 Mod 4 upgrade centers on the Northrop Grumman MK 44 Bushmaster II 30 mm gun integrated with a new sight and operator console.
Sources: NAVSEA MK 38 Mod 4 Delivery
Media
Mk44 Bushmaster II Videos
Related Weapon Systems
Sources
Northrop Grumman 30x173mm Bushmaster Chain GunsPublisher: Northrop Grumman | Note: Supports Mk44, Mk44S, XM813, and GAU-23 family context, Mk310 compatibility, 30 x 173 mm ammunition relationship, manufacturer attribution, and official image/video context. | Accessed: 2026-07-13Northrop Grumman Mk44 DatasheetPublisher: Northrop Grumman | Note: Supports Mk44 facts including ammunition compatibility, dual-feed system, chain-gun operating principle, weight, rate of fire, power requirement, and production/logistics context. | Accessed: 2026-07-13Northrop Grumman 30x173mm Full Ammo Suite BrochurePublisher: Northrop Grumman | Note: Supports 30 x 173 mm round family details and Mk238, Mk239, Mk266, and Mk310 compatibility with the Mk44 or other 30 x 173 mm cannons. | Accessed: 2026-07-13Northrop Grumman Mk44S DatasheetPublisher: Northrop Grumman | Note: Supports Mk44S Stretch growth-variant facts including 30/40 mm configuration, field upgrade path, feed options, weight, and power requirement. | Accessed: 2026-07-13Northrop Grumman XM813 DatasheetPublisher: Northrop Grumman | Note: Supports XM813 variant facts including Mk44S lineage, 30/40 mm configuration, linkless/closed-bolt Stryker Dragoon configuration, weight, power requirement, and recoil-system context. | Accessed: 2026-07-13Northrop Grumman GAU-23 DatasheetPublisher: Northrop Grumman | Note: Supports GAU-23 aircraft-version facts including AC-130J and Harvest Hawk applications, dual feed, side ejection, and weight. | Accessed: 2026-07-13ATK GAU-23 Type ClassificationPublisher: ATK / PR Newswire | Note: Supports the July 2012 ATK announcement that the GAU-23/A 30 mm automatic cannon received U.S. Air Force type classification for AC-130W gunship use. | Accessed: 2026-07-13Army Stryker Increased Lethality DemonstrationPublisher: U.S. Army | Note: Supports Army 30 mm Stryker lethality-demonstration context, including the Kongsberg medium-caliber remote weapon station and precision firing ranges. | Accessed: 2026-07-13DVIDS 2CR First 30mm StrykerPublisher: Defense Visual Information Distribution Service | Note: Supports Stryker Dragoon host-platform context by documenting 2nd Cavalry Regiment receiving the first 30 mm Stryker Infantry Carrier Vehicle - Dragoon in Germany. | Accessed: 2026-07-13DOT&E Stryker ICV-D FY2018 ReportPublisher: Director, Operational Test and Evaluation | Note: Supports XM-813 Stryker ICV-D integration, electric-motor operation, ammunition feed arrangement, and unmanned MCT-30 weapon-system context. | Accessed: 2026-07-13Oshkosh Defense First Stryker MCWS DeliveryPublisher: Oshkosh Defense | Note: Supports Stryker MCWS timeline context for delivery of the first 30 mm Medium Caliber Weapon System test vehicle to the U.S. Army. | Accessed: 2026-07-13U.S. Navy MK 46 Gun Weapon SystemPublisher: U.S. Navy | Note: Supports the MK 46 Mod 2 relationship by documenting the Mk 44 Mod 2 cannon, dual feed, remote/local operation, magazine capacity, rate of fire, and LPD-17/DDG-1000/LCS platform fits. | Accessed: 2026-07-13MSI-DS SEAHAWK DS A2Publisher: MSI-Defence Systems | Note: Supports the DS30M/SEAHAWK DS A2 naval mount relationship and Mk44 cannon integration context. | Accessed: 2026-07-13NAVSEA MK 38 Mod 4 DeliveryPublisher: Naval Sea Systems Command | Note: Supports 2026 MK 38 Mod 4 context by documenting integration of the Northrop Grumman MK 44 Bushmaster II 30 mm gun with the MK 48 Mod 2 sight and MK 134 Mod 0 operator console. | Accessed: 2026-07-13Defence24 Rosomak in UkrainePublisher: Defence24 | Note: Supports 2014 Russia-Ukraine War direct use by reporting Polish-supplied Rosomak IFVs in Ukrainian service and identifying the Hitfist-30P IFV variant's main armament as the 30 mm Bushmaster II Mk44; also supports Afghanistan context through a 2010 Rosomak Hitfist-30P patrol caption. | Accessed: 2026-07-13Ukraine MOD Rosomak APC OverviewPublisher: Ministry of Defence of Ukraine | Note: Supports 2014 Russia-Ukraine War direct use by documenting Rosomak combat variants with Hitfist-30P turrets in Ukrainian service and Ukrainian service-member comments on Bushmaster cannon firepower. | Accessed: 2026-07-13Patria KTO Rosomak PolandPublisher: Patria | Note: Supports 2001 War in Afghanistan context by documenting Rosomaks reaching Ghazni with the Polish ISAF contingent and more than 130 vehicles supporting the Afghanistan mission. | Accessed: 2026-07-13UK MOD Ukraine Support Package Terrahawk PaladinPublisher: UK Ministry of Defence | Note: Supports 2014 Russia-Ukraine War direct transfer context by announcing MSI-DS Terrahawk Paladin air-defense systems for Ukraine through the International Fund for Ukraine. | Accessed: 2026-07-13European Security & Defence Terrahawk VSHORAD DetailsPublisher: European Security & Defence | Note: Supports Terrahawk VSHORAD technical context, including the Mk44 Bushmaster II gun fit, ready-round configurations, and counter-UAS ammunition context. | Accessed: 2026-07-13Ukrainska Pravda Ukraine Deploys Terrahawk PaladinPublisher: Ukrainska Pravda | Note: Supports 2014 Russia-Ukraine War direct use by reporting UK-supplied Terrahawk Paladin systems deployed by Ukraine's Air Force on a MAN HX chassis. | Accessed: 2026-07-13