U.S. Army Yuma Proving Ground is currently testing a variety of systems associated with the Extended Range Cannon Artillery (ERCA) project, including an XM1113 projectile that exceeded 60 kilometers in a May 2018 test fire. Photo: US Army.

The Army is restarting production of Rocket Assisted Projectiles (RAP) for 155mm artillery cannons, introducing a new, redesigned RAP that will extend 155mm 39 caliber gun range to more than 24 miles (40km). As an insensitive munition (IM) high explosive RAP, the new round will be safer and able to accommodate the Precision Guided Kit (PGK) M1156 fuze, providing near-precision strike capability. XM1113 will replace the aging M549A1 rounds produced in the 1970s and 1980s.


XM1113 rocket assist projectile. Illustration: US Army

The new artillery round achieves its extended range capabilities through increased thrust and a redesigned shell shape. “The XM1113 uses a large high-performance rocket motor that delivers nearly three times the amount of thrust when compared to the legacy M549A1 RAP,” said Ductri Nguyen, XM-1113 Integrated Product Team Lead. “Its exterior profile shape has also been streamlined for lower drag to achieve the 40-plus kilometers when fired from the existing fielded 39-caliber 155mm weapon systems.” The traditional high explosive, TNT, inside typical artillery rounds has also been replaced by Insensitive Munition Explosive, which is less volatile and reactive to outside stimuli, such as rocket-propelled grenades, improvised explosive devices, and extremely high temperatures. For instance, if a rocket grenade hits a convoy transporting the rounds, the rounds are less likely to detonate and explode.

The XM1113 is currently planned for Limited Rate Initial Production in Fiscal Year 2022. and will be fielded to M777A2 and the future Extended Range Cannon Artillery 155mm 58 caliber gun.