Reactive armour is a type of vehicle armour used for protecting vehicles, especially modern tanks, against anti-vehicle armour-piercing munitions.
Reactive armour is most effective against shaped charges and hardened kinetic energy penetrators. When a shaped charge strikes the upper plate of the armour, it detonates the inner explosive, releasing blunt damage that the tank can absorb.
Military vehicles are commonly armoured (or armored; see spelling differences) to withstand the impact of shrapnel, bullets, shells, rockets, and missiles, protecting the personnel inside from enemy fire. Such vehicles include armoured fighting vehicles like tanks, aircraft, and ships.
Civilian vehicles may also be armoured. These vehicles include cars used by officials (e.g., presidential limousines), reporters and others in conflict zones or where violent crime is common. Civilian armoured cars are also routinely used by security firms to carry money or valuables to reduce the risk of highway robbery or the hijacking of the cargo.
A rocket-propelled grenade (RPG), also known colloquially as a rocket launcher, is a shoulder-fired anti-tank weapon that launches rockets equipped with a shaped-charge explosive warhead. Most RPGs can be carried by an individual soldier, and are frequently used as anti-tank weapons. These warheads are affixed to a rocket motor which propels the RPG towards the target, stabilized in flight with fins. Some types of RPG are reloadable with new anti-tank grenades, while others are single-use. RPGs are generally loaded from the front.
RPGs with high-explosive anti-tank (HEAT) warheads are very effective against lightly armored vehicles such as armored personnel carriers (APCs) and armored cars. However, modern, heavily-armored vehicles, such as upgraded APCs and main battle tanks, are generally too well-protected (with thick composite or reactive armor) to be penetrated by an RPG, unless less armored sections of the vehicle are exploited. Various warheads are also capable of causing secondary damage to vulnerable systems (especially sights, tracks, rear and roof of turrets) and other unarmored targets.