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A 22 mm rifle grenade is inserted over the firing mechanism on the front of rifles that are equipped with the appropriate spigot-type launcher, either in the form of an integral flash suppressor or a detachable adapter. As with most rifle grenades, it is propelled by a blank cartridge inserted into the chamber of the rifle. A 22 mm (0.87 in) grenade can range from a powerful anti-tank round to a simple finned tube with a fragmentation hand grenade attached to the end. The "22 mm" refers to the diameter of the base tube which fits over the spigot of the launcher, not the diameter of the warhead section, which is much wider.
This measurement practice differs from conventional launched grenades, such as the US 40 mm grenade, which are measured at their widest point, since they are launched out of gun-like barrels. Thus, a 22 mm rifle grenade can easily be as powerful as a 40 mm grenade, in spite of the seemingly smaller size. A 22 mm grenade is launched on the spigot principle, like a spigot mortar; a tube slightly under 22 mm is attached to the end of a rifle barrel to serve as the spigot, and left open on the muzzle end so bullets can be fired through it. The grenade consists of a heavy warhead section of 30–75 mm (1.2–3.0 in) in diameter for the nose, and a lightweight hollow tube for the tail section. The inner diameter of this tube is 22 mm, and fits over the tube attachment on the muzzle with only a small amount of play, to create a good gas seal and promote accuracy. 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.