Semiautomatic rifle with inertial operation

A semiautomatic rifle (10) with inertial operation, comprising an arming unit (11) and an inertial-loading device (12), wherein said inertial-loading device (12) comprises an inertial-spring elastic element (35) inserted in a blind hole (36) of a compression mass (37), wherein said arming unit (11) comprises a breechblock (13), said breechblock (13) housing a firing pin (18), and further comprising a cocking lever (21) equipped with a corresponding spring (22) and with a kinetic mass (23), wherein said spring (22) and said kinetic mass (23) are contained within the movable distance of said arming unit (11), a magazine follower (24) designed to transfer cartridges (20) supplied by a magazine box (25) of said inertial-loading device (12) to said arming unit (11), wherein said magazine box (25) of the inertial-loading device (12) has an opposite end provided with a blind end made by means of at least one plug-like extension (27) of at least one rod (28), which carries a knob (29), on a front free end of said rod (28) wherein the end of a spring (34), blocked by a shaped bushing (38), is inserted on said magazine box (25), said spring (34) bearing upon an extension (26) of a receiver (16) of said rifle (10), wherein said arming unit (11) being functionally associated with said inertial-loading device (12) for loading the cartridges (20) so as to exploit inertia associated with the recoil of the rifle when the rifle is fired, both for operation of said arming unit (11) and for feeding said cartridges (20) from said magazine box (25) to a cartridge chamber.