A locking and recocking assembly with swivel breech-lock and rotating locking head particularly designed for inertially-actuated weapons, which combines in a single assembly all the functions for locking, opening, case ejection and recocking with locking return, required for correct operation of the weapon; those functions were, until now assigned to various components variously assembled on the weapon. The locking and recocking assembly with swivel breech-lock and rotating locking head has the entire mass, required for inertial operation, concentrated in the swivel breech-lock, which is accommodated completely within the supporting structure of the weapon, such as the sheath or barrel extension or breech of the weapon. All this leads to better balancing and stability of the weapon, higher reliability in operation, greater constructive simplicity and ease of assembly and disassembly.