Abstract: A process and apparatus for priming ammunition casings (1) of the type having a bottom (2) connected to a cylindrical lateral wall (3) by an annular flange (4) defining within the casing an annular throat (5) adapted to receive a pyrotechnic priming composition (6). The composition (6) is deposited on the bottom of the casing, and then is introduced into the throat (5) by subjecting the composition (6) deposited on the bottom (2) of the casing to a progressive compression in an oblique direction relative to the axis (X-X') of the casing (1) and directed toward the throat (5), by means of a surface (8) which is caused to turn about the axis (X-X'). This is done with a rotating core (7) that has at its lower end a truncated conical surface that is eccentric to the axis (X-X') of the core (7).