Benelli semi-automatic shotguns operate on the same basic principle of inertial operation with a fixed barrel, utilizing the kinetic energy of gun recoil, which still today represents one of the most important and ingenious innovations of sporting weapons production. This system requires no outlet for gas operation nor barrel recoil but operates by means of a spring freely interposed between locking head and bolt. As the gun recoils during firing, the breech bolt (inert) moves about 4 mm forward, thus compressing the spring. When this is fully compressed, it overcomes breech bolt inertia, thrusting it to the rear under residual pressure, permitting cartridge case extraction and reloading with the conventional system. Spring pressure is designed to delay the opening of the action, which occurs after the shot has left the barrel, and to compensate for the different pressures produced by cartridges of varying power, with no adjustment necessary. The fully automatic operation of this new shotgun eliminates the drawbacks of the barrel recoil system (barrel vibrations during firing needed to brake the system and regulate it when firing powerful ammunition etc.) and those of gas operated type (the need to clean gas outlets, loss of power due to acceleration of the shot charge and adverse effect on the longitudinal shape of the wad and possible malfunctions under adverse climatic conditions). The Benelli system is therefore modern and highly reliable. To this operating system has been added a revolving bolt head of simple and robust shape, which with only two locking lugs, closes the breech axially and perfectly, withstanding any pressure of the cartridge. The modern and revolutionary trigger action is carried out through a system of variable profiles which allows the user to shoot precisely and without jerking in the trigger pull. The pull action is carried out in a smooth and controlled way, without trigger-free pre-run or sudden relaxation after releasing the hammer, thus ensuring the efficacy and safety of the whole system. Finally, the precise synchronization of the movement of the hammer double coupling teeth optimizes the feeding system through combined action with the cartridge drop lever and the top-notch. The cut-off feeding system operates by means of a special “cartridge drop lever”, the outer portion of which protrudes below the receiver and is thus easily reached by the trigger finger.
Upon shooting, the hammer spring forces the cartridge drop lever upwards to disengage it from the carrier latch which, pulled by the carrier latch spring, rotates clockwise to allow a cartridge to exit from the magazine. As the cartridge falls into position on the carrier, it presses against the “cartridge drop lever” which rotates in the opposite direction to prevent a second cartridge from exiting. When the bolt is operated the carrier rises automatically to position the cartridge for introduction in the chamber. In the meantime, the hammer spring, which was compressed during cocking, has freed the cartridge drop lever to return to its resting position. In this way, the carrier latch holds the remaining cartridges in the magazine until the next shot is fired. The end of the cartridge drop lever which protrudes from the receiver is marked with a red point. When the red point is visible, the hammer is cocked and the gun is ready to fire; otherwise, the hammer is not cocked. Thanks to this operation cartridges in the barrel chamber can be easily replaced manually.