Benelli Montefeltro shotguns operate on the basic principle of inertial operation with fixed barrel, utilizing the kinetic energy of gun recoil, which still today represents one of the most important and ingenious innovation of sporting weapon 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 4mm 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 eli...