Sponge grenade

A sponge grenade is a riot control weapon, intended to be non-lethal, which is fired from a 40 mm grenade launcher to cause confusion, or otherwise temporarily disable its target. As a single blunt force object, it is best used when aimed at a particular individual.

The projectile weighs about 28 grams (1 ounce). It is bullet-shaped, with a foam rubber nose and a high-density, plastic projectile body.

It is "less-lethal" munition round for a 40mm M203 or M79 grenade launcher that provides temporary incapacitation through blunt trauma. Minimum engagement range is 10–15 metres, and maximum effective range is 50 metres. Muzzle velocity at 50 metres is 200 feet per second.

Versions of these projectiles fired at a lower muzzle velocity are sometimes used in airsoft games, fired from replicas of the aforementioned launchers.

Potential for injury or death
If used improperly—such as at distances closer than 10 metres—injuries to the targeted individual could prove fatal. Used properly, the weapon is intended to cause no permanent damage, but may, in some cases, cause broken bones, head wounds or permanent damage to eyes. When fired at point blank range, there have been cases of sponge grenades causing death.

Use as a warning shot
According to the Canadian American Strategic Review the rear gunner in a vehicle convoy could use a sponge grenade as their warning shot, instead of live rounds. Vehicle convoys in Iraq and Afghanistan have proven highly vulnerable to suicide bombers driving civilian vehicles. Rear gunners cannot know whether approaching civilian vehicles are driven by innocent civilians, or by enemies. Rear gunners are supposed to warn off vehicles that approach the convoy too closely. If hand signals do not work the gunner is supposed to escalate to firing lethal rounds near the approaching vehicle, which puts nearby pedestrians at risk. If the approaching vehicle ignores the warning shot the gunner is supposed to alter their aim to try to target the vehicle's engine block, to disable it, rather than kill the occupants. A gunner whose weapon has a coaxial grenade launcher would not have to alter their point of aim if the driver ignores the sponge grenade warning shot.

External links and sources

 * More data and a picture from the website of the Federation of American Scientists