The M3A1 propelling charge, known as the ‘Green charge,’ is primarily used in howitzers with tube lengths of 23 or 39 caliber, featuring chamber volumes of approximately 12 and 18 liters, respectively. The charge comprises five propellant bags, numbered from 1 to 5, each containing a defined quantity of single-base powder tailored to operational requirements. Bag number 1, referred to as the base bag, is equipped with four straps sewn onto it, providing rigidity to the charge when tied at the top of bag number 5. The operational scenario determines the number of bags to be used, following the same procedure outlined for the 105 mm caliber.