A rotor for a firearm having a tracks and locks for interaction with at least one firearm bolt with a rotatable head and carrier body may have a reversible lock structure such that locks may be merely turned around in relation to the rotor when one set of lock bosses is worn by the interaction of the lock and bolts when firing. Drive and delinker gears may also be geometrically keyed to the rotor to efficiently divide torque across the gears and to maintain correct timing for the firearm.