New Artillery Rounds to Help Army Reach Longer Distances.

• Author: Gourley, Scott R.

LAS VEGAS, Nevada--A new family of 155mm ammunition is being developed to help the Army achieve its goal of improving the reach of its long-range precision fires.

Even before Russia's invasion of Ukraine--and the resulting spotlight on the likely need for ammunition logistics replenishment--the Army had tapped long-range precision fires as one of its top modernization priorities.

The Army's next generation 155mm artillery ammunition is one part of the campaign to increase the range of its howitzers and its new 58-caliber Extended Range Cannon Artillery platform.

The new cannon is one of 24 new technologies Army Chief of Staff Gen. James McConville has publicly vowed to field by the end of 2023.

The new family of 155mm ammunition is being developed to increase the maximum range of the current howitzer fleet using 39 caliber length tubes. The 39-caliber fleet will replace the current 14-mile range M795 high-explosive projectile with the 18.5-mile XM1128 base-bleed projectile and replace the current 18.5-mile M549A1 rocket-assisted projectile with the 25-mile XM1113 rocket-assisted projectile.

Base-bleed artillery shells expel gas in flight behind the shell to reduce drag and give them longer range.

The 58-caliber Extended Range Cannon Artillery will be utilizing the XM1210 rocket-assisted, high-explosive projectile--formerly designated XM1113ER--to hit targets out to nearly 45 miles.

As noted in the ammunition descriptions, much of the range enhancement relies on the use of either "base-bleed" or "rocket-assisted" designs.

Kyle McFarland, chief technology officer at General Dynamics Ordnance and Tactical Systems, said he expects to provide the shell bodies for the XM1128 and is the systems contractor for the XM1113 "all up" projectile.

The base-bleed design features a relatively small amount of propellant on the back end of the projectile. That propellant is ignited by the gun gases and the burning propellant reduces drag on the projectile to provide a modest range extension. The relatively small amount of propellant used in base-bleed designs requires only minor tradeoffs with the explosive payload.

"By contrast, with the rocket-assisted projectile, the back half of the round is going to be filled with a solid rocket motor with a nozzle at the end to direct its thrust," he said.

"That nozzle has some elements in it that are also ignited by the gun gases, which then ignite the rocket motor. The rocket motor gives you a limited amount of...