Northrop Grumman's 50mm XM913 Chain Gun on a test stand for range trials, showing the muzzle brake. (Photo: Northrop Grumman)
How next-generation chain guns will boost US Army MICV capabilities
Northrop Grumman has confirmed that the US Army has now ordered a total of 16 of its latest generation 50mm XM913 Bushmaster Chain Guns.
This weapon was developed by the company in close cooperation with Picatinny Arsenal and leverages the earlier 35mm Bushmaster III in service with Denmark, Estonia and the Netherlands and selected by Sweden, all for use on the BAE Systems Hägglunds CV90... Continues below
This analysis article originally appeared in December's Decisive Edge Land Warfare Newsletter.
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The 50mm XM913s are for US Army testing as well as being provided to both contenders, General Dynamics Land Systems and Rheinmetall American Vehicles, building prototypes of the XM30 Mechanized Infantry Combat Vehicle (MICV), previously known as the Optionally Manned Fighting Vehicle.
Each contractor is required to deliver up to 11 prototype vehicles as well as two ballistic hulls, armour elements and digital engineering data by mid-2026. The XM30 MICV will have a digital architecture to make upgrades easier and a remote-controlled turret (RCT).
The XM30 MICV is replacement for the US Army’s Bradley M2 Fighting Vehicle, a total of 6,785 were built including 400 for Saudi Arabia, with final deliveries early in 1995.
The Bradley has been constantly upgraded, especially in the area of survivability, but is in urgent need of replacement as previous efforts to do so have collapsed.
The main armament of the M2 is the Northrop Grumman 25mm M242 dual-feed Chain Gun with a 7.62mm co-axial machine gun and a twin launcher for the Raytheon TOW anti-tank guided weapon (ATGW) on the left side.
When fielded, the XM30 MICV will provide a step change in survivability and firepower as the XM913 Bushmaster has a longer range and fires a new suite of 50x228 mm ammunition with increased target effect.
Two natures of this ammunition have been developed by General Dynamics Ordnance and Tactical Systems – High Explosive Air Bursting (HE-AB) and Armour Piercing Fin Stabilised Discarding Sabot- Tracer (APFSDS-T) – while Northrop Grumman has developed the Target Practice-Tracer (TP-T) with significant numbers of these already manufactured for the demonstration phase.
The XM1204 HE-AB round can be programmed for three modes depending on the target being engaged. These are point detonation, point detonation delayed and air burst which makes the projectile detonate above the target.
The XM1203 APFSDS-T will have a conventional rather than a depleted uranium penetrator while the XM1202 TP-T will have similar ballistics to the XM1204
XM913s supplied for the US Army have a dual-feed system but for other potential customers it will also be available in a linkless feed configuration.
According to Northrop Grumman, the complete weapon with receiver, feeder and barrel with muzzle brake weighs 314kg and only requires a power supply of 3.5hp at 270 and 28V DC.
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For the MICV it is fully stabilised and integrated into a RCT. This is coupled to a computerised fire control system capable of engaging static and moving targets while the XM30 is stationary or moving with a high first-round-hit probability.
While the MICV stows fewer rounds than the Bradley it will require less to neutralise a target as the 50mm ammunition is far more effective.
The gunner can select single shot, burst or fully automatic rates of fire with the empty cartridge cases ejected forward out of the turret.
Northrop Grumman is now in full-scale production of the latest 30mm XM813 Bushmaster for the US Army and US Marine Corps plus an increasing number of export customers. This is also referred as the MK44S with the S in the designation meaning stretched. Technically, the stretched part is not the actual barrel but the feeder/receiver.
In a statement Northrop Grumman noted: “All variants of the 30 x 173 mm cannon can be configured to meet the customer’s requirement.”
The first production US Army application was for the Kongsberg Medium Calibre Remote Controlled Turret installed on the GDLS XM1296 8x8 under the Stryker Lethality Upgrade Programme.
Following another competition the contract went to Oshkosh Defense Systems who used the double-V hull Stryker for the Upgrade Lethality Programme with a new turret, but there were delays with this effort.
More recently it has been fitted to the marine corps’ Amphibious Combat Vehicle 30 (ACV-30) which is also fitted with a Kongsberg RCT armed with 30mm MK44S and 7.62mm coaxial MG.
Other recent production applications include Australia (Redback), Norway (upgraded CV90), Finland (CV90), Poland (Rosomak), Spain (Dragoon) and UAE (new 8x8).
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