Abstract: The invention relates to a breech wedge for artillery cannon, of a type that includes means for supporting a primer-cartridge magazine that is driven in translation and rotation under the control of an assembly consisting of a rack and pinion. This first pinion is mounted on a shaft supporting a second pinion, which cooperates with a second rack integral with a fork sliding on the wedge. A control lever pivots on the breech sleeve and supports a roller, which cooperates with a groove in the fork in such a way as to slide the fork on the breech wedge. A second roller cooperates with a groove in the wedge in such a way as to cause the wedge to slide on the breech sleeve.