M1299 ERCA super-cannon: the US Army throws in the towel and leaves American artillery without a solution

Launched in 2019, the Extended-Range Cannon Artillery, or ERCA, program and the M1299 super-cannon, were to allow the US Army to regain the advantage in terms of artillery, while the M109 Paladin and its 39 caliber, offered performances much lower than those of the European Archer, Pzh2000 and Caesar, and their 52 caliber tubes.

Thus, where the range of the Paladin, with conventional shells, caps at 24 km, the European systems exceed 40 km. Worse still, China and Russia have also undertaken to equip their armies with these 8 meter long cannons, with the Chinese PCL-181 and the new 2S35 Russian Koalitsiya-sv.

The ERCA program, one of the pillars of the BIG 6 super program, had to meet this challenge, by equipping the M109 with a new 58 caliber tube to give birth to the M1299, allowing it to propel conventional shells up to 70 km. If the first tests were encouraging, the technical difficulties encountered in recent months have, it seems, got the better of the program.

Too rapid wear of the 58 caliber XM907 L/58 barrel 

Just over a year ago, in January 2023, the US Army announced that tests of its M1299 self-propelled gun, an M109 equipped with the 58 caliber XM907 tube, showed signs of rapid wear. An investigation was then carried out to understand the reasons for this excessive fatigue, and especially how the problem could be circumvented.

The Pzh2000 is one of these European artillery systems which entered service 15 to 20 years ago, equipped with a 52 caliber tube (52 times the caliber of the weapon, i.e. 8,06 m), whose range and precision are much greater than those of 39 caliber tubes, as for the American M109.

Indeed, the longer an artillery tube is, the greater the mechanical and thermal stresses during firing. If, for a naval artillery system, it is easily possible to increase the thickness of the tube, to increase its resistance, this obvious solution cannot easily be transposed to a self-propelled gun, for which the weight gain only a thicker tube would considerably alter the mobility and stability of the vehicle.

American engineers therefore, for a year, looked for a solution to maintain the length of the XM907 gun, without significantly increasing its mass, to increase its resistance to stress.

These difficulties are not surprising. Indeed, already, the 52 caliber tubes of the Caesar, Pzh2000, Archer and K9, wear significantly more quickly than the 39 caliber tubes previously used, this imposing, particularly in Ukraine, an increased need for regeneration of the European systems installed. implemented by the armies of Kyiv.

The US Army announces the abandonment of its M1299 super-gun from the ERCA program in the 2025 budget.

Obviously, efforts to find an applicable solution for the M1299 were in vain. The US Army has, in fact, announced, as part of the presentation of these requests concerning the 2025 budget (which begins on October 1, 2024), the abandonment of this program and the associated investments.

US Army M1299 super-gun
The M1299 is an M109 chassis equipped with a 58 caliber (9 m) tube, to achieve a range of 70 km with a conventional shell. However, American engineers were unable to resolve the problems of premature wear of the tube, leading to the abandonment of the program.

On the occasion of the presentation of the US Army's 2025 forecast budget on March 8, Doug R. Bush, Assistant Secretary of the US Army in charge of acquisitions, confirmed that despite the conclusion of the prototyping phase, having made it possible to deliver the 20 expected XM1299s, the difficulties encountered did not allow moving into the production phase.

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