BS-1 (RSA-86) — noiseless 30mm grenade launcher was developed in the mid 1960-ies in TSNIITOCHMASH for use in the noiseless grenade launcher complex "Silence", where it was placed on in service with special forces automatic AKMS. But from about the beginning of the eighties in the modification of the BS-1M composed of noiseless grenade launcher 6S1 "Canary" was mounted on the AKS-74УБ with silencer PBS-4.
assumnig underbarrel grenade launcher BS-1 (RSA-86) is a separate loading weapon which fires a grenade is charged into the barrel from the muzzle, and lifting (throwing) charge, is served in the breech. At the time of firing the powder gases of a blank cartridge propel the piston located in the rear of the barrel, driving a piston and a grenade to a speed of over 100 m/s (175 m/s for BS-1M). After the departure of grenades from the barrel, the piston stops in the barrel, locking under high pressure powder gases in a closed space. After they cool down and the pressure drops to a safe it is possible to reload the grenade launcher, that is loading into the trunk of the new grenades (in this case the piston is precipitated ago), the ejection of the spent cartridge case and chambering a new cartridge expelling. Reload weapon ammunition is from detachable box magazine (capacity of 8 rounds for BS-1 to BS or 10-1M) located in the handle of the grenade, with a longitudinally sliding rotary shutter rifle type. To fire the grenade launcher has a trigger and manual safety. Use grenades of two types — military armor-piercing incendiary (symbol VOG-T) and training with inert warhead. In both cases, the stabilization of the grenade in flight is rotating, which on the body of the grenade is made ready protrusions to follow the grooves in the barrel of the grenade launcher. For aiming when shooting from a grenade launcher on the pad of a rear sight of the machine are equipped with special folding sight used in conjunction with the standard front sight machine. To install a grenade launcher on the machine are used special attachment, with an early version (AKMS) and late (AKS-74УБ) have a different system of brackets and incompatible footprints.
Used on the AK-74U in the game Call of Duty: Black Ops (mission Revival)