An automatic firearm having an inertial automation system comprises a barrel, which is movable along its own axis, a bolt support with a bolt, a recoil spring, a buffer spring and a hammer spring, a trigger mechanism, an ammunition feed mechanism, a mechanism for coordinating the actual firing, and a bolt support latch. The springs and the mechanism for coordinating the actual firing ensure a constant-value recoil force during automatic fire. Technical result consists in the improvement of the shooter's operating conditions, reduced vibration, and decreased bullet dispersion.

A bolt assembly has a rear block configured for connection at the rear end of the bolt passage, a bolt carrier configured to reciprocate in the bolt passage, a support element between the rear block and the bolt carrier, a first spring between the support element and the rear block, the bolt carrier defining a bore, the support element including a guide rod slidably received in the bore, and a second spring encompassing the guide rod, having a rear end abutting the support element, and a forward portion received in the bore. The bolt carrier may include a bolt carrier body, and the bolt carrier may include a weight portion movably connected to the bolt carrier body. The weight portion may define a through hole receiving an intermediate portion of the guide rod and an intermediate portion of the second spring.

A bolt assembly has a rear block configured for connection at the rear end of the bolt passage, a bolt carrier configured to reciprocate in the bolt passage, a support element between the rear block and the bolt carrier, a first spring between the support element and the rear block, the bolt carrier defining a bore, the support element including a guide rod slidably received in the bore, and a second spring encompassing the guide rod, having a rear end abutting the support element, and a forward portion received in the bore. The bolt carrier may include a bolt carrier body, and the bolt carrier may include a weight portion movably connected to the bolt carrier body. The weight portion may define a through hole receiving an intermediate portion of the guide rod and an intermediate portion of the second spring.

Apparatuses, systems, and methods are provided for selectively changing the force required to cycle a firearm. In some embodiments, an apparatus is provided with at least two biasing members or springs where one biasing member generates a softer or smaller force than another biasing member. When manually cycling the firearm, the softer biasing member reduces the effort required for a person to cycle the firearm, which reduces the likelihood of injury and allows people with a broader range of physical abilities to cycle the firearm. Then, when the firearm fires a round, the other biasing member provides the greater force required to cycle the firearm in a conventional, semi-automatic or automatic manner.

Apparatuses, systems, and methods are provided for selectively changing the force required to cycle a firearm. In some embodiments, an apparatus is provided with at least two biasing members or springs where one biasing member generates a softer or smaller force than another biasing member. When manually cycling the firearm, the softer biasing member reduces the effort required for a person to cycle the firearm, which reduces the likelihood of injury and allows people with a broader range of physical abilities to cycle the firearm. Then, when the firearm fires a round, the other biasing member provides the greater force required to cycle the firearm in a conventional, semi-automatic or automatic manner.

A firearm buffer includes a buffer casing having a casing chamber with open and closed ends, and buffer weight within the casing chamber. A buffer plug is received in the open end of the buffer casing. A cross pin extends through at least a portion of the buffer plug retaining the buffer plug on the buffer casing. A locking pin is longitudinally displaceable between a first position and a second position. In the first position, the locking pin is engaged with the cross pin and retains the cross pin in position with respect to the buffer plug. In the second position, the locking pin is disengaged from the cross pin such that the cross pin is removable from engagement with the buffer plug thereby permitting disassembly of the firearm buffer. A method of assembling a firearm buffer is also included.

A firearm buffer includes a buffer casing having a casing chamber with open and closed ends, and buffer weight within the casing chamber. A buffer plug is received in the open end of the buffer casing. A cross pin extends through at least a portion of the buffer plug retaining the buffer plug on the buffer casing. A locking pin is longitudinally displaceable between a first position and a second position. In the first position, the locking pin is engaged with the cross pin and retains the cross pin in position with respect to the buffer plug. In the second position, the locking pin is disengaged from the cross pin such that the cross pin is removable from engagement with the buffer plug thereby permitting disassembly of the firearm buffer. A method of assembling a firearm buffer is also included.

A delayed rotary blowback mechanism integrated into a firearm bolt and carrier subassembly. A plurality of radial locking lugs are configured at a rear end of the bolt and seat within a mating profile of an upper receiver interior or integrated trunnion in a fully chambered position. A plurality of chamfered locations are configured between the lugs and a receiving profile in the barrel or trunnion for influencing linear to rotational motion of the bolt. A cam pin extends upwardly from the bolt and seats through a circumferentially directed slot configured within the bolt carrier. Upon initiating of the discharge cycle, signaled by the round traveling through and out the end of the barrel, the chamfered configuration results in the bolt and cam pin rotating within the carrier and the lugs subsequently separating from the receiver or trunnion, with the bolt and associated carrier retaining sufficient inertia to cycle through the discharge cycle to the set position concurrent with reloading a subsequent cartridge.

A delayed rotary blowback mechanism integrated into a firearm bolt and carrier subassembly. A plurality of radial locking lugs are configured at a rear end of the bolt and seat within a mating profile of an upper receiver interior or integrated trunnion in a fully chambered position. A plurality of chamfered locations are configured between the lugs and a receiving profile in the barrel or trunnion for influencing linear to rotational motion of the bolt. A cam pin extends upwardly from the bolt and seats through a circumferentially directed slot configured within the bolt carrier. Upon initiating of the discharge cycle, signaled by the round traveling through and out the end of the barrel, the chamfered configuration results in the bolt and cam pin rotating within the carrier and the lugs subsequently separating from the receiver or trunnion, with the bolt and associated carrier retaining sufficient inertia to cycle through the discharge cycle to the set position concurrent with reloading a subsequent cartridge.

A delayed blowback mechanism integrated into a firearm bolt and carrier subassembly. A cam pin extends from the bolt and, upon initiation of the cartridge discharge cycle, engages a guiding clearance or pocket configured within the firearm upper receiver for providing recoil and discharge force attenuation in a radial delayed fashion during cycling of the bolt carrier group. Recoil attenuation between the cam pin and upper receiver clearance can be provided alone or assisted by chamfer or angled contour to either or both of the radially projecting and rear contact surfaces of the bolt locking lugs and the opposing inward projections configured within the barrel extension grooves. In any variant, the bolt and associated carrier retain sufficient inertia to cycle through the discharge cycle to the set position concurrent with reloading a subsequent cartridge.