The XM913 Bushmaster autocannon is an effective weapon; all that remains is to develop a way to shoot down low-flying drones with greater accuracy.

The advent of large numbers of cheap, attritable, and deadly drones has been among the biggest gamechangers on the modern battlefield since the introduction of tanks and aircraft. Unlike those platforms, however, there has been no quick or easy solution to countering the threat they pose. Various passive defensive measures—from add-on armor to netting—have been employed by both sides in the ongoing war in Ukraine. New electronic warfare (EW) weapons, as well as lasers, are also being tested.

However, the oldest approach—though far from the most efficient—has been reliance on old-fashioned kinetic weapons: anti-aircraft or other machine guns, which can be found around the world in abundance. These weapons already exist, are battle-tested, and can be relatively cost-effective if they can be proven to work reliably against aerial threats.

This week, the United States Army’s Project Manager, Maneuver Ammunition Systems office called for industry to develop a system employing a 50mm cannon that could be used to counter the threat from aerial drones.

In a Sources Sought notice issued on Monday, the US Army stated it was seeking developers that could “integrate a 50mm ammunition solution to effectively track, engage, and defeat Class 1, 2, and 3 UAS threats.” According to the notice, the hardware would need to be based around Northrop Grumman’s XM913 Bushmaster 50mm autocannon assembly, with applications due on August 31, 2026.

Before being tasked with building a prototype, entrants will need to provide, “A detailed description of the company’s capabilities pertaining to C-UAS, proposed C-UAS system architecture, fire control/sensor integration, detailed draft test or demonstration plan, and how the platform will successfully employ the 50x228mm ammunition against the specified target set.”

The US Army Wants to Counter a Range of Drones

The goal of the program does seem quite ambitious, as it is meant to be used against a rather broad range of drones, from Group 1 to Group 3 platforms. 

• Group 1 drones are the smallest class of UAS defined by the US Department of Defense. These can weigh up to 20 pounds, and operate at altitudes under 1,200 feet above ground level.
• Group 2 includes a tactical UAS that weighs 21 to 55 pounds, with a maximum speed of 250 knots and a 3,500-foot ceiling.
• Group 3 includes medium-sized military drones that can weigh up to 1,320 pounds and can fly up to 18,000 feet Mean Sea Level (MSL).

It is notable that Group 4 and 5 drones—or large-scale drones operating with heavy firepower at a great height, such as the MQ-9 Reaper—are not included in the proposal, perhaps in recognition that a machine gun is not likely to do much against them.

Groups 1 through 3 must operate closer to the ground, potentially making them a more attractive target. All three groups of drones have been a regular ongoing threat to military vehicles in Ukraine, but the US military has faith that one weapon could be the solution, at least with the right tracking system. 

About the Army’s XM913 Autocannon

The XM913 50mm autocannon was developed for the United States Army to serve as a weapon on the Mechanized Infantry Combat Vehicle (MICV), which is intended to eventually replace the aging M2 Bradley Infantry Fighting Vehicle (IFV).

As the name suggests, the XM913’s barrel is 50 millimeters wide, or around 2 inches. The projectile it fires is four times larger than a .50 caliber (12.7mm) bullet, the largest conventional rifle round, and can be highly effective for use against lightly armored vehicles and other “soft” targets. This certainly extends to drones, which are lightweight and therefore poorly armored by design.

The Bushmaster chain gun, an evolution of the Mk44S and Bush III cannons for ground platforms, had been previously tested as a counter-rocket, artillery, and mortar (C-RAM) weapon, and a counter-unmanned aerial vehicle (C-UAV) system. The platform, which weighs just less than 700 pounds, can fire in single-shot mode, burst, or up to 200 rounds per minute. As designed, it is chambered to fire two types of munitions, including XM1204 High Explosive Airburst with Trace (HEAB-T) and XM1203 Armor-Piercing Fin-Stabilized Discarding Sabot with Trace (APFSKS-T). The weapon utilizes a dual-feed system that allows gunners to instantly switch between the two rounds. HEAB-T is already on track to becoming the US Army’s standard high explosive (HE) ordnance.

About the Author: Peter Suciu

Peter Suciu has contributed to dozens of newspapers, magazines and websites over a 30-year career in journalism. He regularly writes about military hardware, firearms history, cybersecurity, politics, and international affairs. Peter is also a contributing writer for Forbes and Clearance Jobs. He is based in Michigan. You can follow him on Twitter: @PeterSuciu. You can email the author: Editor@nationalinterest.org.

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