The grenade launcher screws onto the forward end of the rifle barrel and locks into place by means of a spring-loaded plunger mounted in the front sight base of AK-47 rifles. The sight for the launcher is mounted on the rear sight base. A valve is fitted to the right side of the gas block to allow the gas to be shut off (prevented from leaving the barrel via the gas port) when grenades are fired.
When using the rifle to launch grenades, a special rubber recoil pad is used and a special 10-round magazine inserted. This magazine has a filler block that prevents it from being used with "normal" (i.e. bulleted) cartridges. There is also a regular version of this rifle as well that was not designed to shoot grenades. Regular AK-47 Polish variant picture