The US’s railgun dream is roaring back to life — this time as a last-ditch shield for Guam and the mainland against a new era of missile and drone threats.
This month, Naval News reported that General Atomics is reviving its railgun technology for potential integration into the US’s expanding air and missile defense architecture, including Guam’s defenses and the Golden Dome initiative.
Displayed at the Association of the US Army annual meeting, the company’s multi-mission railgun system—capable of firing tungsten warhead projectiles at speeds of up to Mach 6—was pitched as a solution for terminal defense against ballistic and cruise missile threats.
Mike Rucker, head of General Atomics Electromagnetic Systems (GA-EMS) Weapons and former US Navy railgun program manager, asserted that prior technical challenges, including barrel wear, have been resolved, though operational fieldability remains under development.
Despite the cancellation of US railgun programs in 2021, General Atomics continued R&D efforts, attracting international interest from unnamed partners. Parallel developments in Japan, China, France and Germany underscore global momentum, with Japan and China unveiling ship-mounted prototypes and trilateral collaboration underway in Europe and Asia.
Rucker emphasized Guam’s vulnerability to Chinese long-range fires, including Dong Feng ballistic and submarine-launched cruise missiles (SLCMs), noting that current defenses are optimized for a scenario involving a North Korean limited attack with a few missiles. The company’s renewed pitch aligns with the US’s urgency to reinforce Indo-Pacific deterrence amid rising regional tensions.
Meanwhile, Japan and China have continued to develop railgun technology. Japan advanced its railgun tech rapidly, shifting from proof-of-concept to operational milestones in two years. In October 2023, Japan tested a medium-caliber electromagnetic railgun at sea, firing 40-millimeter, 320-gram projectiles with 20 megajoules of energy.
By April 2025, the prototype on JS Asuka had achieved a muzzle velocity of 2,000 meters per second, firing without rail erosion, offering a cost-effective missile defense alternative. In September 2025, Japan conducted the world’s first live ship-mounted railgun firing at sea, hitting a target vessel near Mach 7, aiming to counter hypersonic threats and cut reliance on costly interceptors.
China has also progressed despite setbacks. In May 2024, it tested an electromagnetic launcher that fired a smart bomb 15 kilometers into the stratosphere at over Mach 5 before malfunctioning.
By July 2025, China unveiled the “X-rail gun,” capable of firing 60-kilogram projectiles at Mach 7 to 400-kilometer ranges, marking a significant leap from its 2018 prototype and aiming to match missile-like performance at artillery costs.
While Japan and China’s railgun efforts seem focused on ship-based weapons, efforts to renew US railgun research may focus on land-based applications for missile defense. That shift likely stems from the maxed-out condition of Arleigh Burke destroyers, aging and uneconomical-to-refurbish Ticonderoga cruisers, and the uncertain development of the DDG(X) program.
Railguns could boost terminal defense by increasing magazine depth, providing an additional layer against missile and drone threats targeted at US critical overseas or mainland facilities.
To illustrate these threats, China has developed containerized cruise missiles that could be concealed in merchant shipping. Innocuous merchant ships near Guam could turn out to be concealed cruise missile and drone launchers.
A multi-vector saturation attack consisting of ballistic missiles, cruise missiles and drone swarms could stretch Guam’s layered defenses, which have yet to address the challenge of integrating diverse systems into a comprehensive shield.
In terms of mainland missile defense, the US has only 44 Ground-Based Midcourse Defense (GMD) interceptors to counter an intercontinental ballistic missile (ICBM) attack – perhaps too few to defeat a saturation attack involving dozens of ICBMs with penetration aids and decoys.
However, US military facilities in the mainland may be facing a more surreptitious threat than incoming ICBMs. Breaking Defense reported in October 2024 that the US military has raised concerns over hundreds of drone incursions over domestic installations in recent years, raising concerns about surveillance vulnerabilities and operational security.
The report notes that many of these incursions go undetected and that sightings at sensitive bases like Langley—home to F-22s critical for maintaining US air superiority—have prompted scrutiny.
Those security lapses may hint at the vulnerability of those critical facilities against a surprise drone swarm attack, with Ukraine’s Operation Spider Web providing a vivid illustration of what could happen – drones launched from pre-positioned inconspicuous trailers managed to inflict significant damage on Russia’s strategic bomber force, destroying several irreplaceable Tu-95 and Tu-22 nuclear-capable bombers.
Similarly, China has developed containerized drone swarms that could be weaponized, smuggled through US borders and pre-positioned near key US military facilities. Analysts suggest surprise drone attacks from within the US mainland could prove difficult to stop.
Michael Bohnert mentioned in a Military Times article this month that the vastness of most countries reduces the effectiveness of air defense systems, as tens of thousands of such systems may be needed to defend even a modest-sized country.
Considering Bohnert’s logic, the US’s size significantly complicates defense against a swarm drone attack coming from within its territory, presenting many possible concealed or covert launch sites and enabling numerous flight paths.
Against such a threat, railguns may share a common vulnerability with conventional guns and missile-based short-range air defense (SHORAD) systems, namely, the high expenditure and cost of ammunition. Soft-kill measures such as jamming could have only a limited impact against autonomous drones, which do not rely on external controller signals to find and destroy their targets.
By comparison, directed-energy weapons (DEWs) such as lasers and high-power microwaves (HPMs) may obviate the need for physical ammunition and may offer substantially lower costs per shot compared to missile interceptors.
While Russia and Israel have reportedly deployed laser weapons in combat, atmospheric factors can limit range, thermal limitations can cap their effectiveness against multiple targets and delicate components may face durability concerns in harsh environments.
Overall, while the renewed pitch for railguns could bolster US missile defense, issues such as systems integration persist. At the same time, low-cost drone swarms launched from within the US mainland may pose an even more insidious threat than an enemy missile attack.
