22 mm grenade

There are typically a series of rings machined around the perimeter of the tube, which serve as baffles to slow any escaping high-pressure gases created on launch until the grenade is clear of the launcher, and sometimes a metal o-ring to create a final seal and to lock the grenade in place until pressure has risen high enough.

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.

[1] Many NATO small arms, such as the West German Heckler & Koch G3, French MAS-36/51, MAS-49/56 and FAMAS, British SA80, and American M16/M4 are equipped to launch 22 mm grenades without an adapter.

The same 22 mm thread diameter for these rifles has also been referred to as a "STANAG muzzle device" size for flash hiders and other attachments by civilian firearm traders.

Israel and Norway[2] both employed Belgian-made Mecar 22 mm adapters for the Mauser K98k rifle.