To fire the grenade, firstly a special blank cartridge is loaded into the weapon. There is often some sort of cutoff device on
gas operated rifles that can be engaged to disable the gas piston, both to eliminate the possibility of a live round chambering itself, and to prevent any of the gas being tapped off, which might affect the accuracy and range of the grenade. The tail of the grenade is slipped over the muzzle attachment, where it indexes itself so the aiming mark is on the top. The rifle is lined up with the target, butt to the ground, and held to the proper angle to ensure the correct ballistic trajectory, a skill which must be learned in training. This can be done by eye, but some rifles, such as the
Yugoslavian M59/66 (SKS) and
Zastava M70, have built in flip-up ladder sights that allow for accurate ranging of the shots, by giving a graduated series of "rungs" which correspond with various ranges. The rifle is aligned with the target, and the user looks through the ladder sight, adjusting the angle until the sighting mark on the tip of the grenade matches the proper range on the sight. The trigger is then pulled and the high-velocity gases rush down the barrel. The gas is slowed by the obstructing grenade, and the low-pressure, high-velocity gas transforms into low-velocity, high-pressure gas very rapidly, which forces the grenade off the launcher at a relatively high speed, whereupon it follows a ballistic arc to the target. A rifle grenade cannot be easily or safely fired directly at a target, and is always used for
indirect fire; the closer the target, the higher the angle the rifle is held, much like a mortar. == Adoption ==