The barrel of the Maxim Sokolov machine gun, caliber 7.62 x 54 mm, serves to give the direction of the bullet's flight when fired. Inside, it has a cartridge chamber and a grooved channel with four grooves that wind from the left, up and right. The grooves serve to give the bullet a rotational movement during its flight. The gaps between the grooves are called fields; the distance (in diameter) between two opposite fields determines the caliber of the barrel channel; it is equal to 7.62 mm. The ends of the barrel are thickened: the front one - to increase the area of the cut and enhance the kick; the rear one - for greater strength. At the rear end of the barrel there are: a) two pins on the square part for connecting the barrel to the frame; b) a bronze nut for stopping the barrel in the tubular socket of the casing; c) an annular groove for placing the rear seal (asbestos winding), preventing water from leaking from the casing; d) on the barrel edge - two grooves for movement of the groove protrusions of the warhead of the bolt.