US Army fires hypersonic warhead from repurposed supergun in first Yuma Proving Ground live test.

On July 30, 2026, the U.S. Army executed the first full-scale live-fire test of a hypersonic warhead using a cannon-based test system at Yuma Proving Ground in Arizona. Conducted in partnership with the DEVCOM Armaments Center and Lawrence Livermore National Laboratory, the trial utilized the Heavy Artillery Test System, a static asset derived from the canceled Strategic Long Range Cannon program, to accelerate an Integrated Launch Package to high velocity. The methodology isolates terminal impact dynamics and payload lethality while eliminating the high procurement costs and multi-variable logistics of full missile flight campaigns.

The live-fire demonstration validated a specialized Integrated Launch Package and electronic Safe-and-Arm Device engineered to protect the warhead structure, internal fuze, and telemetry sensors against extreme gun-barrel acceleration and shock loads. By substituting costly missile booster stages with a large-caliber artillery system, the program establishes a repeatable, high-throughput testing architecture to assess terminal penetration, fuze timing, and target degradation under controlled kinetic conditions.

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The gun is said to be the Heavy Artillery Test System (HATS) from the Strategic Long Range Cannon (SLRC), a program intended to develop a giant artillery gun capable of engaging targets beyond 1,000 miles with rocket-assisted, precision-guided projectiles. (Picture source: US Army)

On July 30, 2026, the U.S. Army announced that Yuma Proving Ground in Arizona had completed the first full-scale live-fire test of a hypersonic warhead launched from a cannon-based test system, creating a new way to evaluate terminal effects without expending a costly hypersonic missile. The event concluded a two-year effort involving Yuma Proving Ground, the DEVCOM Armaments Center and Lawrence Livermore National Laboratory, which converted a missile warhead into a gun-launched projectile able to survive the pressure, acceleration and shock generated inside a very large-calibre barrel. The testing does not reproduce a hypersonic missile's booster ignition, sustained hypersonic flight, aerodynamic heating, guidance corrections, manoeuvring or complete mission performance.

Its purpose is to remove those unrelated variables when engineers need to answer a narrower question about whether a warhead will function and produce the intended effect at impact. The cannon used is assessed to be the Heavy Artillery Test System (HATS) developed from the cancelled Strategic Long Range Cannon (SLRC) effort, originally intended for a mobile artillery gun with a planned range beyond 1,000 miles, or 1,609 km. The live shot validated a complete firing sequence rather than only the warhead's impact. Crews first verified telemetry channels, high-speed cameras, range instrumentation, and target preparation before a test-purpose truck positioned the Integrated Launch Package at the breech. The fuze was then armed, the payload loaded, the propelling charge inserted and personnel moved into protected bunkers before the test director authorized firing.

Telemetry monitored the firing, while high-speed imaging captured barrel exit, flight behaviour and the terminal interaction with the target. By accelerating only the warhead and its protective launch package, the gun reduced the number of failure points unrelated to lethality and allowed the test team to concentrate on warhead integrity, fuze survival, payload structural condition and target effects. Earlier inert firings had already demonstrated that the package could be launched safely and had produced enough data to modify the sabot, payload interfaces and firing configuration before an explosive warhead was introduced. The successful live event therefore confirmed that the complete chain, from handling and loading to launch survival, fuze operation and impact measurement, worked under the selected test conditions.

The economic argument for such cannon-launched hypersonic testing is based on the mismatch between the cost of a complete hypersonic flight and the limited amount of information it provides about terminal lethality. A full test requires a flight-ready missile, booster, propulsion hardware, guidance and navigation systems, telemetry equipment, range radars, tracking aircraft or ships, safety coordination, and access to a large test corridor. Individual hypersonic prototypes can cost several million dollars before range and support costs are included, and the production rate of developmental rounds limits how often they can be fired. Yet penetration, casing breakup, fuze timing, fragmentation, blast transfer and target failure occur during the final milliseconds of the trajectory. For those measurements, the preceding flight primarily serves to deliver the warhead at a defined velocity, angle and orientation.

A large-calibre gun can reproduce a substantial portion of that final kinetic state without consuming the complete missile. The method also permits more shots within the same budget, allowing engineers to compare explosive fills, penetrator shapes, casing thicknesses, fuze delays, impact angles and target materials under controlled conditions. More frequent tests could therefore generate statistically stronger datasets, expose inconsistent behaviour and improve the calibration of computer models before the design reaches an integrated flight campaign. The most difficult engineering problem was not achieving high velocity but ensuring that the payload survived a launch environment more severe than the one it would encounter on an operational missile. Missile boosters accelerate their payloads over a relatively long interval, while a gun generates a sharp chamber-pressure rise and transmits very high axial loads through the projectile over the length of the barrel.

Those loads can deform structural components, break electrical connections, damage explosive interfaces, or cause a fuze to fail before the payload reaches the target. Lawrence Livermore National Laboratory and the DEVCOM Armaments Center therefore created a gun-hardened Integrated Launch Package rather than loading an operational warhead directly into the cannon. The package used a purpose-built sabot to center the payload in the bore, transfer acceleration forces into the assembly, and protect the warhead during barrel travel. Engineers modelled interior ballistic pressure, acceleration, vibration, deformation and load paths before moving to proof firings. DEVCOM also integrated an electronic Safe-and-Arm Device that had to remain safe during transport and loading, withstand the launch shock and function at the correct point before impact.

Repeated engineering reviews also examined structural margins, explosive safety, fuze reliability, sabot behaviour and compatibility between the warhead, launch package and gun. The central requirement was therefore to ensure that any terminal failure reflected the warhead design itself rather than damage created artificially by the cannon launch. The firing system is assessed to be the Heavy Artillery Test System (HATS), a static test asset linked to the Strategic Long Range Cannon (SLRC) program. The SLRC was intended to provide the U.S. Army with a ground-based artillery weapon capable of firing rocket-assisted precision projectiles beyond 1,000 miles, compared with tens of kilometres for conventional 155 mm artillery.

Concept configurations paired the cannon with an 8x8 Oshkosh M1070 Heavy Equipment Transporter, a detachable gun carriage and a rear trailing section, producing a weapon that could be moved strategically but would need to be emplaced before firing. The planned organization called for four guns per battery and eight personnel per weapon. Its target set included air defense radars, surface-to-air missile launchers, command posts, logistics centers, long-range fires units, and other nodes supporting anti-access and area-denial (A2/AD) networks. The concept promised a deep-strike weapon with greater magazine depth than aircraft and potentially lower ammunition cost than missiles, but it also introduced major problems in transport, emplacement, targeting, barrel wear, projectile manufacture, rate of fire, and survivability after launch.

Congress terminated dedicated funding in FY2022 before the planned prototype demonstration. The programme's strategic rationale had already weakened after the United States left the Intermediate-Range Nuclear Forces (INF) Treaty in 2019, as the US Army could then pursue ground-launched ballistic, cruise and hypersonic missiles in the 500 to 5,500 km range band that the treaty had previously prohibited. Reusing HATS at Yuma avoids the mobility and battlefield-survivability requirements that undermined SLRC while retaining its ability to accelerate a full-scale payload to a high-energy terminal condition. The cannon adds a new specific capability to a wider U.S. hypersonic test architecture that includes laboratories, wind tunnels, rocket sleds, component trials, and complete missile flights.

The Holloman High Speed Test Track in New Mexico, for instance, measures 15.54 km and uses solid rocket motors to accelerate instrumented sleds along a rail. In 2022, the U.S. Air Force recovered a reusable sled after it travelled at 6,400 ft/s, or 1,951 m/s, equivalent to Mach 5.8 under the test conditions. Holloman can evaluate rain erosion, seeker behaviour, material survivability, high-speed separation, dispense mechanisms, guidance components, and selected aerothermal loads over a longer exposure period than a HATS cannon shot. Recovery also allows engineers to inspect cracks, deformation, coating loss, sensor damage, and structural failures after the run rather than relying only on telemetry. The Yuma cannon addresses a different portion of the problem because it is optimized for full-scale impact and terminal energy transfer against a representative target.

Full missile flights remain indispensable for validating booster ignition, propulsion, stage separation, thermal protection, navigation, guidance, control, manoeuvring and mission performance across the intended trajectory. Nevertheless, the value of the layered approach is that it assigns each engineering question to the least expensive facility capable of answering it. Cannon shots can test impact physics, sleds can test high-speed environmental exposure and subsystems, and flight trials can be reserved for complete integration. The reuse of HATS also fits a six-century pattern in which oversized artillery was developed whenever existing artillery weapons could not produce the required range, penetration, or payload effect, then abandoned when its operational costs became greater than its military value.

During the 1453 Siege of Constantinople, the Ottoman army used the Basilic, also known as Urban's cannon, with a bore near 760 mm, to fire stone projectiles weighing 500 to 600 kg against the Theodosian Walls, whose masonry sections reached 5 to 12 m in thickness. Its firing rate of three to seven rounds per day was acceptable only because smaller cannon and mechanical siege engines could not generate comparable breaching potential. In 1918, Germany's Paris Gun used several centuries of improved metallurgy, propellant, and precision machining to fire a 106 kg shell to 130 km, reach an apogee of 42.3 km, and achieve a muzzle velocity near 1,640 m/s. 

However, its 34 m barrel eroded so rapidly that shells had to be numbered and fired in progressively larger diameters, while the trajectory required correction for Earth's rotation. During the Second World War, the over-engineered 800 mm Schwerer Gustav shifted the German requirement from range to penetration, firing 4.8- to 7-tonne projectiles over 37 to 47 km against reinforced fortifications. But the gun weighed 1,350 tonnes, required prepared railway tracks, a firing crew of roughly 250 and several thousand personnel for transport, construction, security and support, while barrel life was limited to roughly 250 rounds.

Cold War weapons such as the U.S. 280 mm M65 Atomic Cannon and Soviet 2A3 Kondensator gave oversized artillery a nuclear mission before tactical missiles became sufficiently reliable. Project HARP later used an extended 16-inch gun to study low-cost high-altitude launch, while Project Babylon proposed a 156 m-long, 1 m-bore weapon intended to send payloads beyond 700 km. Precision-guided bombs, cruise missiles and ballistic missiles disqualified these systems because they could manoeuver, correct their course and continue accelerating after launch, while superguns remained constrained by fixed firing positions, barrel erosion, heavy ammunition and vulnerability to counterattack.

The SLRC attempted to restore strategic artillery through rocket assistance, digital fire control, precision guidance and modern materials, but its cancellation confirmed that those new technologies did not remove the basic penalties of size, logistics and survivability. The HATS now performs a narrower and more defensible function: it remains fixed, fires under controlled range conditions and uses the extreme acceleration of an oversized cannon to generate repeatable terminal data for hypersonic warhead development.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.

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