RPG, or rocket-propelled grenade, is a loose term describing hand-held, shoulder-launched anti-tank weapons capable of firing an unguided rocket equipped with an explosive warhead. RPG is a transliteration of РПГ, the Russian abbreviation of реактивный противотанковый гранатомёт (transliterated as "reaktivniy protivotankoviy granatomyot"), which translates to the English phrase "reactive anti-tank launcher." Thus rocket-propelled grenade is a backronym.
Most modern main battle tanks (MBTs) are not vulnerable to hand-held RPGs, and this was demonstrated in the Israel-Hezbolla war of 2006. RPGs are still used very effectively against lightly-armoured vehicles such as armored personnel carriers (APCs) or unarmored wheeled vehicles, as well as against buildings and bunkers. They can still be a threat to an MBT under certain tactical conditions. One exception is the RPG-29, the most advanced model, which uses a tandem-charge high explosive anti-tank warhead to penetrate explosive reactive armor (ERA). It is capable of destroying some modern MBTs such as the T-90. In August 2006, an RPG-29 round penetrated the frontal ERA of a Challenger 2 tank during an engagement in al-Amarah, Iraq.
The most widely distributed and used RPG in the world is the Soviet Union-developed RPG-7. The Soviets developed the basic design of this RPG during World War II, combining important design features of the US Bazooka and the German Panzerfaust. Today, advanced armies such as that of the United States, have implemented armor on their tanks that are invulnerable to grenades. However, new rounds have been developed to use with the RPG-7 launchers, that can defeat advanced armor types such as ERA.
The RPG launcher is a hollow tube that concentrates the rocket exhaust to create an over-pressure within the tube. This over-pressure propels the warhead at a higher speed than from the specific impulse of the rocket alone. This higher speed is necessary for the rocket to be stable in flight.
The launcher is designed such that the rocket exits the launcher without discharging an exhaust that would be dangerous to the operator. In the case of the RPG-7 the rocket is launched by a gunpowder booster charge, and the rocket motor ignites only after 10 meters. In some other designs the rocket burns completely within the tube.
The high-temperature rocket exhaust is hazardous fifteen to twenty meters to the rear of an RPG launcher. The launcher must be cleaned periodically, as built-up residue will result in an excess of over-pressure, causing the sighting mechanism to be driven into the operator's eye when the rocket is fired. Blindness in one eye often results.
An RPG is an inexpensive way to deliver an explosive payload a distance of 100 yards (91m) with moderate accuracy. Substantially more expensive, wire-guided rockets are used when accuracy is important. These rockets trail a thin wire behind them during firing and can be steered by the operator while in flight. In 1982, British troops were sent to the Falklands War armed with a number of wire-guided MILAN anti-tank missiles even though there were no Argentine tanks in the Falklands Islands. The British used these expensive weapons to destroy Argentine bunkers at longer ranges. The British also used cheap 66 mm M72 LAW unguided rockets and recoilless 84mm against Argentine bunkers. The popularity and usefulness of such weapons prompted the U.S. military to field the SMAW, the U.S. equivalent of the RPG.
The HEAT (high explosive anti-tank) round is a standard shaped charge warhead, similar in concept to those used in tank cannon rounds. In this type of warhead, the shape of the explosive material within the warhead focuses the explosive energy on a copper (or similar metal) lining. This crushes the metal lining and propels some of it forward at a very high velocity. The resulting narrow jet of metal can punch through the armor of most APC's and IFV's. However, the warhead on older RPG systems is too small to penetrate the main armor of most modern battle tanks, although it is still capable of causing secondary damage to vulnerable systems (especially sights, tracks, rear and roof of turrets) and can disable or destroy most lightly armored or unarmored vehicles.
Specialized warheads are available for illumination, smoke, tear gas, and white phosphorus. Russia, China, and many former Warsaw Pact nations have also developed a fuel-air explosive (a/k/a "thermobaric") warhead. Another recent development is a tandem HEAT warhead capable of penetrating reactive armor.
Accuracy limits the standard RPG-7 to a practical range of 50 m, although it can reach 150 or even 300 m in skilled hands. It has an indirect fire (bombardment) range to 920 m, limited by the 4.5-second self-destruct timer.*
So-called PRIGs (Propelled Recoilless Improvised Grenade) were improvised warheads used by the Provisional IRA.
One of the first instances when it was used by terrorists was on 13 January 1975 at the Orly airport in France when Carlos the Jackal together with another member from the PFLP used two Soviet RPG-7 grenades to attack an Israeli El Al airliner. Both missed, and one of them hit a DC-9 of Yugoslav Airlines instead.
Because of the inherent inaccuracy of the RPG, the operator must fire relatively close to the intended target, increasing the chances of being spotted and captured, shot or killed. Most modern armies deploy anti-tank guided missiles (ATGM) as their primary infantry anti-tank weapon, but the RPG can still be effectively employed against tanks under certain tactical conditions, especially urban warfare, where they are favored by low-tech armies. They are most effective when used in restricted terrain as the availability of cover and concealment can make it difficult for the intended target to spot the RPG operator.
The operator must move after firing the RPG as the ignition of the rocket generates a flash visible to the enemy and usually leaves a smoke trail leading back to the firing position. In Afghanistan, Mujahideen RPG shooters who remained in position after firing were often killed by Soviet counter-fire.
When deployed against personnel, the warhead can be aimed at a solid surface to detonate, popular choices being trees or buildings. Another option is an indirect method of firing the warhead over the intended target area at ranges of 800–1000 m where the warhead would detonate automatically. More skilled shooters can use the RPG self-destruct feature to make it explode over the enemy at closer range.
Although they can be used against hovering helicopters, they should not be confused with anti-aircraft shoulder fired surface-to-air missile systems such as the Stinger or SA-7 Grail. Furthermore, firing at steep angles poses a danger to the user, because the backblast from firing reflects off the ground. In Somalia, militia members sometimes welded a steel plate in the exhaust end of an RPG's tube to deflect pressure away from shooter when shooting upwards at US helicopters. RPGs are used in this role only when more effective weapons are not available.
Multiple shooters were also effective against heavy tanks with reactive armor: The first shot would be against the driver's viewing prisms. Following shots would be in pairs, one to set off the reactive armor, the second to penetrate the tank's armor. Favored weak spots were the top and rear of the turret.
Afghans sometimes used RPG-7s at extreme range, exploded by their 4.5- second self-destruct timer, which calculates to an almost 1-km range. This performed expedient indirect antipersonnel bombardment and was sometimes used to discourage reconnaissance by aircraft.
Chechen fighters formed independent "cells" that worked together to destroy a specific Russian armored target. Each cell contained small arms and some form of RPG (RPG-7V or RPG-18, for example). The small arms were used to button the tank up and keep any infantry occupied while the RPG gunner struck at the tank. While doing so other teams would attempt to fire at the target in order to overwhelm the Russians' ability to effectively counter the attack. To further increase the chance of success, the teams took up positions at different elevations where possible. Firing from the third and higher floors allowed good shots at the weakest armor (the top).
When the Russians began moving in tanks fitted with ERA (Explosive Reactive Armor), the Chechens had to adapt their tactics, because the RPGs they had access to were unlikely to result in the destruction of the tank. 2 or more RPG teams would position themselves in such a way that they could all hit the same section of a tank, but from different angles. Usually rebels would first hit the tank with a large IED to blow the tracks off it so it couldn't move then rebels would fire at the reactive armor with an RPG to create a spot where the base armor was exposed. The other team would aim for this spot, since it was now as vulnerable as if there was no ERA on the tank at all. These were crude, but apparently effective, way to get the effect of a tandem warhead without actually having one.
At the time, Soviet helicopters countered the threat from RPGs at landing zones by first clearing them with anti-personnel saturation fire. The Soviets also varied the number of accompanying helicopters (two or three) in an effort to upset Afghan force estimations and preparation. In response, the Mujahideen prepared dug-in firing positions with top cover, and again, Soviet forces altered their tactics by using air-dropped fuel-air bombs on such landing zones. As the U.S.-supplied Stinger surface-to-air missiles became available to them, the Afghans abandoned RPG attacks.
Both of the Black Hawk helicopters lost by the U.S. during the Battle of Mogadishu in Somalia in 1993 were downed by RPG-7s. In Iraq and the second Afghanistan campaign, RPGs were deployed with mixed success against Coalition helicopter forces.