Navy’s Stealthy Zumwalt Destroyer Has Finally Fired Its 30mm Guns For The First Time

The test is a promising sign that the ship is slowly making progress in proving its basic capabilities.

byJoseph Trevithick|
Cannons photo


More than a year after a pair of 30mm Bushmaster II cannons were installed on the U.S. Navy's first-in-class USS Zumwalt, the ship has fired the weapons for the first time in a test. These guns, fitted instead of two larger 57mm guns, are one of a number of controversial changes to the stealth destroyer's design over the years.

Zumwalt conducted what the Navy described as a “structural test fire” of the two Mk 46 Mod 2 Gun Weapon Systems (GWS), which are mounted on top of the ship's helicopter hangar toward the stern, at the Naval Air Weapons Center Weapons Division Sea Test Range off Point Mugu, California on May 16, 2020. Pictures first appeared of the Mk 46s installed on the destroyer in February 2019, which The War Zone

was first to report.

“The privilege of being a 'first-in-class' ship includes having the opportunity to systematically conduct testing across the breadth of systems installed onboard the ship," Navy Captain Andrew Carlson, the Zumwalt’s commanding officer, said in a statement. "The real plus is conducting those tests, such as today’s live fire with the Mark 46 GWS, which provide tangible evidence of combat capability maturation."

Zumwalt fires one of her Mk 46s during the May 16 test., USN
Zumwalt spotted in San Diego with her Mk 46s installed in February 2019., MrWasabi

Each Mk 46 Mod 2 is a remotely-operated turret containing a single 30mm Mk 44 Bushmaster II automatic cannon. The operators use control consoles within the ship to aim the weapon by way of visual, low-light-level, and infrared video cameras, as well as a built-in laser rangefinder, inside the turret. These gun systems, versions of which are found on San Antonio class landing platform docks and Littoral Combat Ships (LCS) equipped with the Surface Warfare Mission Package, are intended primarily for close-in defense against smaller surface threats, such as small boat swarms.

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"Today's event is the first in a chapter of live fire test events over the next year that will prove the lethal capability that these ships will bring to the fight,” Navy Lieutenant Commander Tim Kubisak, the Zumwalt Test Officer for the Program Executive Office for Integrated Warfare Systems, who was present for the live-fire test, said in a statement. However, this is a chapter that has been a long time coming at best and at worst it is a reflection of the watered-down combat capabilities of what is arguably the service's most advanced surface combatant, something you can read about more in this past War Zone piece. This particular test event wasn't even intended to gauge the effectiveness of the cannons against simulated threats, but merely to make sure that firing them didn't damage the mounts, sensors, or other electronic systems or any other adjacent parts of the ship.

The USS Zumwalt pulls into Pearl Harbor in Hawaii., USN

The 30mm cannons themselves have been a source of controversy. In 2012, the Navy decided to install them in lieu of a pair of larger 57mm Mk 110 guns, arguing that the Mk 46 GWS was actually a more effective weapon for the intended role. This was despite the fact that the Mk 110 gun has a higher rate of fire and greater range than Mk 44 cannon in the Mk 46 GWS. The 57mm weapons also have a wide set of ammunition options, including programmable rounds with an airburst mode and "smart" shells, which enables to them to engage a broader array of potential targets, including some aerial threats.

A Mk 110 gun in the turret on the bow of the first-in-class Littoral Combat Ship USS Freedom., USN
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Regardless of whether or not the Navy made an accurate assessment of the Mk 46 GWS's capabilities, the smaller guns definitely come in a package that is decidedly less stealthy than the fully encapsulated mounts that were to have held the Mk 110s. These mounts would have been similar in broad respects to how the Mk 110 is installed on the bow of Sweden's Visby class corvettes. The arrangement would have allowed the barrels to be stowed completely inside the turret when the guns were not in use, helping to keep the Zumwalt as stealthy as possible. Other features added over the years have also degraded the ship's stealthy qualities.

The turret for the 57mm Mk 110 gun on a Swedish Visby class corvette. The proposed Mk 110 mounts of the Zumwalt class destroyers would have been similar., Poxnar/Wikicommons

At present, the 30mm cannons are also the Zumwalt's only usable large-caliber guns. In 2016, the Navy canceled plans to buy any of the special Long-Range Land Attack Projectiles (LRLAP) that were to go along with the ship's pair of 155mm main guns, which are installed inside stealthy fully encapsulated turrets. This decision came after the cost of each LRLAP round ballooned to an exorbitant $800,000

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The service is exploring other possible ammunition types to actually make these guns operational, but, for the foreseeable future, they're effectively dead weight. The Zumwalt also has 80 Mk 57 vertical launch system cells, which can accommodate various weapons, including quad-packed RIM-162 Evolved Sea Sparrow Missiles (ESSM) and Tomahawk land-attack cruise missiles.

The Zumwalt's combat capability has long been a point of contention, in general. The Navy commissioned the ship in 2016 and had agreed to take delivery of it from shipbuilder Bath Iron Works that year with many of its systems, such as the Mk 46s, only partially installed, if they were at all. Congress interceded by passing a law making it illegal for the service to accept delivery of the ship until its combat systems were officially activated. In the end, the Navy only formally received the ship in April, despite having been operating in a limited fashion for four years now.

By every indication, in its final form, the Zumwalt, as well as its two sister ships, the USS Michael Monsoor and the future USS Lyndon B. Johnson, will still be extremely advanced and capable ships. However, years of cost-cutting measures and other controversial decisions, including truncating the class to just three ships, down from the originally planned fleet of 32, are likely to keep the ships acting primarily as testbeds for new systems and tactics, techniques, and procedures over the course of their service lives.

Zumwalt and Michael Monsoor are already assigned to a developmental unit, Surface Development Squadron 1, that the Navy stood up last year. The Lyndon B. Johnson is set to join them after its commissioning, which was originally supposed to occur in 2017. The ships are likely to find themselves attached to other forces for actual deployments, but the extent of those operational activities remains to be seen. It will difficult for the trio to make persistent contributions.

It is certainly good to see progress being made on getting Zumwalt's weapon systems to an operational state, but it comes years after the stealth destroyer was supposed to fully enter service and shows that the ship still needs significant work to get anywhere near to reaching its full potential.

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