FIELD: systems of automatic weapon, weaponry and systems of automatic small arms. SUBSTANCE: the oblique-grooved device for bore locking has two modifications: with one kinematic pair within the drive and driven links, and with two kinematic pairs within two drive links and a driven link with a two-sided engagement located between them. The links have bulges and grooves inclined relative to the breechblock longitudinal axis. Engagement of the links and locking of the breechblock are effected when the bulges enter the conjugate grooves and blockings of the driven link in the position of complete engagement of the links. The trigger mechanism with control of the modes of firing through the trigger does not need any use of a special change lever to pass from single-shot fire to continuous fire. Fire control is effected by changing the trigger stroke. At an incomplete pressing of the trigger single-shot fire is conducted, at a complete pressing - continuous fire. To ensure an absolute reliability of conducting of single-shot fire, the trigger mechanism is provided with a keeper of the mode of firing. At a pressed pedal the possibility of complete pressing of the trigger is blocked. The machine gun with a balancing gear has four modifications formed by two methods for cartridge feed-belt-feed and magazine-feed ones, and by two methods of breechblock unlocking a compensation one and with a direct drive from a gas engine. The compensation method of breechblock unlocking is featured by the initial period of the shot counteracts the force of pressure of powder gases and ensures a delay of the moment of breechblock unlocking in accordance with the weapon ballistic requirements. In the compensating mechanism of breechblock unlocking use is made of a low-power gas engine operating for compensating spring compression only. Automatic action of the weapon is effected due to the half-free breechblock. In the machine gun modifications with breechblock unlocking directly from a gas engine automatic action of the weapon is effected due to the use of the energy of powder gases rejected from the bore to the gas engine with a drive mechanism to the breechblock. In all machine gun modifications use is made of a device for balancing of the masses of the weapon movable parts, making it possible to prevent the influence of impact moments of the loading mechanism on fire. In machine gun modifications with a magazine feed of cartridges use is made of a longitudinally multiple- row magazine with a doubled capacity as compared with a box standard magazine. To provide the universality as far as the ammunition stock is concerned, the machine gun is provided with a magazine adapter which make it possible to use also drum-type and box magazines beside the longitudinally multiple-row one. EFFECT: simplified automatic action of the weapon, reduced weight of the weapon and enhanced adaptability to its manufacture. 53 cl,10 dwg, 1 ex
