"Insufficient Ammunition, US Restarts 'Super Cannon' Faces Mockery: 'Waste Utilization'"

[Global Times Special Correspondent Xie Zhao, Global Times Reporter Ma Jun] The ongoing conflict in the Middle East has increasingly highlighted the U.S. military's ammunition stockpile shortages. Against the backdrop of the Pentagon's eagerness to replenish low-cost long-range strike weapons, the U.S. Army suddenly announced the resumption of the "super cannon" with a range of over 1,000 miles (approximately 1,600 kilometers). Experts interviewed by the Global Times on August 6 indicated that existing information shows that the U.S. military's revival of this "super cannon," which had been shelved as early as 2022, is actually a case of "waste utilization," intended for testing hypersonic weapons. Previous test data has already proven that relying on the "super cannon" to solve the U.S. military's long-range strike ammunition shortage is not feasible.

On August 4, Reuters reported that individuals familiar with U.S. military internal data revealed that during the ongoing five-month conflict between the U.S. and Iran, the U.S. military has consumed most of the global stock of land-based long-range precision missiles. Among them, the U.S. Army's Tactical Missile System (ATACMS) and the new generation Precision Strike Missile (PrSM) have been "almost entirely" utilized, and nearly half of the stock of Tomahawk cruise missiles has also been used. Worse still, the U.S. military faces significant challenges in quickly replenishing these expensive long-range precision missiles; for example, the annual production of Tomahawk cruise missiles in recent years has only been in the dozens, and although the Pentagon plans to increase its production capacity to over 1,000 per year, this cannot be achieved in a short time.

In this context, the U.S. Army suddenly announced that the "super cannon," previously considered a new generation of long-range precision strike weapon, has recently completed test firings. The U.S. website "Defense" reported on August 4 that the U.S. Army completed live-fire testing of a hypersonic warhead based on a cannon launch system at the Yuma Proving Ground in Arizona on July 30. Relevant documents indicate that the cannon used in this test is the Heavy Artillery Test System (HATS), derived from the previously shelved Strategic Long Range Cannon (SLRC) project.

Reports indicate that the SLRC was an ambitious plan by the U.S. Army aimed at building a "super cannon" with a range of over 1,000 miles. According to the Pentagon's initial plans, the ultra-long-range shells fired by this "super cannon" could significantly reduce costs. U.S. Defense News stated that theoretically, the shells fired by the SLRC would have tactical performance close to that of the Tomahawk cruise missile, but at only one-fifth the cost, approximately $400,000.

However, reality quickly doused the Pentagon with cold water. The U.S. military found during testing that to enable the shells to travel over a thousand kilometers, the barrel and projectile needed to withstand extreme pressure and high temperatures, far exceeding the limits of existing materials. This necessitated the development of entirely new high-temperature, high-strength materials, and imposed extremely high requirements on the manufacturing process of the barrel. Additionally, relying solely on traditional propellants would not achieve such long ranges; the SLRC plan proposed a composite launch scheme of "traditional barrel launch + rocket boost," but encountered new challenges such as complex projectile separation and multi-stage ignition. The U.S. military also envisioned equipping the projectile with an air-breathing ramjet engine, but this technology is not yet mature and would significantly increase costs. Furthermore, achieving precise strikes at such long ranges would require equipping the ultra-long-range shells with small guidance systems capable of withstanding the immense shock and overload during launch. These extremely challenging technical hurdles led to the SLRC project being quietly shelved in 2022 after incurring massive expenses.

Chinese experts interviewed by the Global Times indicated that although the U.S. Army has restarted the Heavy Artillery Test System, its intention is no longer to advance the development of the "super cannon," but rather to "utilize waste" by transforming it into a testing platform for hypersonic weapons. Because the immense destructive effect of hypersonic weapons partly derives from their massive kinetic energy upon impact, HATS can accelerate test projectiles to hypersonic speeds to simulate and evaluate their terminal effects and lethality during actual impacts. The "Defense" website's "Battlefield" channel reported that the Lawrence Livermore National Laboratory and the U.S. Army's Combat Capabilities Development Command Armaments Center announced the successful first full-scale live-fire test using HATS on July 30. If this new testing method based on ultra-long-range shells can be widely applied, it may provide solutions to the long-standing challenges in the development of U.S. hypersonic technology: obtaining meaningful test data without the need for the costly and complex manufacturing of actual hypersonic missiles. The U.S. Army believes this capability could significantly accelerate the development process of hypersonic weapons and has attracted interest from multiple hypersonic projects.

However, the report acknowledges that this test by the U.S. military only proves the feasibility of the principle, and it remains unclear to what extent the data collected can simulate the actual conditions of hypersonic weapons in flight. The extreme overload during the launch of ultra-long-range shells is distinctly different from the environment of hypersonic missiles in flight, and there is a general consensus that the test data obtained through HATS cannot be directly applied to all hypersonic flight research.      

Experts indicate that the U.S. military has effectively abandoned the unrealistic plan of using the "super cannon" as a long-range strike capability, and the latest tests of HATS have instead exposed the U.S. military's shortcomings in hypersonic basic testing facilities.