Need A 50mm Cannon For Your Bradley Fighting Vehicle Replacement Design? Just Ask The Army

The U.S. Army is considering handing out 50mm XM913 Bushmaster automatic cannons to companies working on possible replacements for the service’s Bradly Fighting Vehicles. At least one defense contractor is already pitching a design using this weapon, which reflects a growing Army interest in larger guns for its armored fighting vehicles as potential opponents, particularly Russia, are also up-gunning their fleets.

On May 30, 2019, the Army provided new details on the potential “government furnished equipment” deal, which the service had first announced it was looking into the month before, via FedBizOpps, the U.S. government’s main contracting website. If the plan goes ahead, companies working on proposals for what is formally known as the Optionally Manned Fighting Vehicle (OMFV) program could receive an XM913 as early as July 1, 2019. This would initially only support work on integrating the weapon into their design. Ammunition for live firing tests would be available in August 2019. 

The package would also include the XM913’s ammunition handling system, which is almost as important as the gun itself. It is a computerized automatic arrangement that allows the gunner to pick certain ammunition types within the magazine in order to best engage certain target sets. The weapon can even take down small unmanned aerial vehicles and low-flying helicopters using proximity-fuzed rounds. The Army did not specify what types of ammunition it will provide along with the gun.

The Army’s contracting notice says that only two complete guns systems would be available in total, suggesting that the Army could ask for them back after a certain amount of time in order to send them to other competitors. As it stands now, likely entrants include General Dynamics Land Systems Griffin III, a version of the KF41 Lynx from Rheinmetall and Raytheon, and a variant of BAE Systems’ CV90. The Army has also recently reviewed Germany’s Puma armored fighting vehicle.

The Griffin III already packs the XM913 gun. At least at present, the Army is not officially mandating that proposed designs use this cannon, but has reportedly made it clear that they would prefer that the vehicle carry some sort of 50mm weapon.

General Dynamics’ Griffin III with its 50mm XM913 gun at maximum elevation., Joseph Trevithick

The XM913 is a fairly mature design. The gun is a refined example of the Bushmaster III automatic cannon design, which Alliant Techsystems, or ATK, first brought to market more than a decade ago. The Bushmaster III itself had leveraged decades of work done on earlier examples of the Bushmaster family, including the 25mm M242 cannon on the Bradley Fighting Vehicle. In 2014, ATK announced that its aerospace and defense components would merge with Orbital Sciences Corporation, which resulted in the creation of Orbital ATK. Northrop Grumman bought this company in 2018.

The initial Bushmaster III was as 35mm cannon, but was convertible into 50mm with minimal modification by using ammunition that fired larger diameter projectiles, but that used same cartridge base dimension. The Army, for a time, considered potentially up-gunning the Bradley to use the 35mm version.

In addition, starting around 2010, the Army explored the possibility of using a 50mm variant of the Bushmaster III to shoot down small unmanned aerial vehicles, as well as artillery shells and rockets. To this day, the service continues to employ a ground-based version of the Navy’s Phalanx Close-in Weapon System (CIWS) named Centurian, which features a 20mm Vulcan cannon, in this role. 

The gun the Army developed as part of this Extended Area Protection and Survivability program, or EAPS, featured a longer receiver to accommodate longer, guided projectiles with programmable warheads. The service eventually shelved the EAPS effort and its gun. 

A US Army briefing slide giving a rough overview of the EAPS concept and showing a rendering of the modified Bushmaster III., US Army

Though the XM913 leverages experience from the EAPS program, it is more closely related to the original 35/50mm Bushmaster III and uses the same sized ammunition as the initial design, Northrop Grumman confirmed to The War Zone in an Email. The company delivered the first example of this improved cannon to the Army in 2018.

The service also evaluated an advanced 40mm design from BAE Systems, which you can read about more here, last year, but appears to have decided not to pursue that option. Companies vying from the Bradley replacement contract can reportedly opt to use a smaller 30mm gun if they design cannot accommodate a 50mm weapon.

The Army is already in the process of adding the 30mm XM813, a variant of the smaller Bushmaster II, onto some of its Stryker wheeled armored vehicles. In December 2017, the first examples of these variants, known as the Stryker Dragoon, which was an interim design, arrived in Europe. On May 23, 2019, the service announced that it had awarded contracts to five companies to develop an improved turret design based on its experience with those vehicles. A week later, it emerged that Senators working on crafting the U.S. defense budget for the upcoming 2020 Fiscal Year had proposed almost tripling the funding for modifying Army Strykers to carry the 30mm guns.

Concerns that potential opponents, especially “great power competitors” such as Russia and China, are developing armored vehicles that out-gun the Army’s existing armored fleets, as well as those in the Marine Corps, are driving these efforts to increase firepower across the board. In particular, the Russians are very actively pursuing a number of different designs that use a multi-purpose 57mm cannon. Russian firms have explored adding turrets with this gun onto armored fighting vehicles and heavy armored personnel carriers and are also developing a vehicle focused primarily on short-range air defense, known as the Derivatsiya-PVO.

So, while the Army may be willing to accept 30mm cannons in the near term to help close the gap, the service clearly sees the potential for a more firm requirement for larger guns in the future. This, in turn, has reportedly raises fears that if potential Bradley replacements don’t take this in account from the very beginning, that it could lead to time-consuming and costly development programs and modification efforts to add in a bigger gun in the future. 

This is likely what drove the Army to make clear its unofficial preference for 50mm guns and what is now pushing it to consider just providing the weapons to competitors outright. In November 2018, the service were already “contemplating a longer proposal development period . . . and concurrent bid sample delivery,” in part to provide more time to competitors to work on the issue of the main gun, according to Inside Defense.

A US Army briefing slide from 2014, showing the XM813 in relation to an “Enhanced Bushmaster III 50mm.”, US Army

The Army’s Bradley replacement schedule remains relatively aggressive, with the goal of down-selecting to two designs in early 2020. Each of the winning companies would build 14 prototypes for a head-to-head competition. The service wants to begin actually replacing Bradleys by 2026.

It remains to be seen what designs will meet the rest of the Army’s requirements, but it seems increasingly clear that the winning vehicles will be armed with 50mm cannons, or at least have the ability to fit them in the future.

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Joseph Trevithick Avatar

Joseph Trevithick

Deputy Editor

Joseph has been a member of The War Zone team since early 2017. Prior to that, he was an Associate Editor at War Is Boring, and his byline has appeared in other publications, including Small Arms Review, Small Arms Defense Journal, Reuters, We Are the Mighty, and Task & Purpose.