The invention relates to a method for manufacturing cylinders (1) for cartridge cases, carried out in a rotary press machine, wherein a composition (2) of essentially plant origin is made available in a precise volume and weight, the cavities (3) of cylindrical molds (4) adapted to said cylinders (1) are fed with said composition (2), for each cylinder, said composition (2) is compressed in the cavity (3) between on the one hand, two, lower and coaxial, cylindrical dies namely a peripheral die (5), capable of sliding axially in the mold (4) and a central die (6) capable of sliding axially independently in the die (5) and on the other hand, an upper die (7), the distance between the dies (5) and (7) defining the height of the cylinder, and the cylinders obtained are ejected.