The 6S1 “Kanareyka” (6C1 «Канарейка» – Canary) noiseless grenade launcher system was created to arm Soviet Spetsnaz units for operations behind the enemy lines. The system consists of a host 5.45mm AKS-74UB suppressed assault rifle with a 30mm 6G17 (6Г17) noiseless grenade launcher attached below the barrel. Other elements of the system include the 5.45x39mm 7U1 (7У1) subsonic ammunition and the 7G23 (7Г23) HE-I grenades, launched using the special PKhS-19 (ПХС-19) 7.62x39mm blank cartridges.
The host weapon is a specially modified AKS-74UB rifle, fitted with a PBS-4 sound suppressor, a mounting bracket on the barrel, and a special forend that allows installation of the 6G17 grenade launcher.
The 6G17 noiseless grenade launcher is an improved version of the 6G16 / GSN-19 special purpose grenade launcher, which was a part of the “Tishina” system, based on a suppressed 7.62mm AKM or AKMS rifle. The 6G17 “Kanareyka” noiseless grenade launcher uses a captive piston system, built into the rear of the barrel to contain powder gases and thus achieve almost noiseless and flash-less launch of the 30mm projectile. The 7G23 High Explosive Iincendiary grenade is loaded from the muzzle and is held in the barrel using special retaining spring. Propelling blank cartridges are loaded from the detachable box magazine using a conventional manually operated rotary bolt action. Eight propelling rounds are contained in each magazine, which is placed into the pistol grip of the launcher. Upon firing, powder gases push the internal piston violently, which, in turn, propels the grenade out of the barrel with a muzzle velocity of about 115 meters per second. The piston is then stopped inside the barrel at the internal constriction in the bore, containing high pressure combustion gases in a closed volume, and thus avoiding any flash and most of the “bang”. After a short while, the launcher can be reloaded first by ejecting a fired propelling cartridge and releasing remaining powder gases into the atmosphere, and then by loading a fresh propelling load into the chamber and a new grenade into the muzzle, resetting the internal piston.
The grenade launcher sight was mounted on the host rifle, and there were no provisions for the “stand-alone” use of the 6G16 grenade launcher without its host.
Compared to its predecessor, the 30mm “Kanareyka” grenade launcher offered a slightly more effective 30mm grenade with a slightly longer range and a better destructive effect. Visually, the new 30mm grenade differed from its predecessor by not having a tail rod. However, the effectiveness of the 5.45mm subsonic ammunition in the AKS-74UB rifle was not very inspiring, and the system soon faded into the obscurity. It is believed that very few of these systems were produced during the late 1980s, and issued to selected Spetsnaz units. Few of these systems may have seen some action during the final years of the Soviet invasion to the Afghanistan, but there are no firm proofs on that – yet.