The M203 propelling charge, known as the ‘Red charge,’ is designed for exclusive use in 39 and 52 caliber howitzers, with tube lengths and chamber volumes of approximately 18 and 23 liters, respectively, and ER (Extended Range) projectiles.

It consists of a single red propellant bag numbered 8S or 9, associated with zone 9 on the howitzer. Additional components include an initiator assembly that ensures uniform combustion of the main propellant, a muzzle flash reducer, a de-coppering liner, and an erosion control element.