Rocket-propelled grenade

Predecessor weapons The static nature of trench warfare in World War I encouraged the use of shielded defenses, even including personal armor, that were impenetrable by standard rifle ammunition. This led to some isolated experiments with higher caliber rifles, similar to elephant guns, using armor-piercing ammunition. The first tanks, the British Mark I, could be penetrated by these weapons under the right conditions. Mark IV tanks, however, had slightly thicker armor. In response, the Germans rushed to create an upgraded version of these early anti-armor rifles, the Tankgewehr M1918, the first anti-tank rifle. In the inter-war years, tank armor continued to increase overall, to the point that anti-tank rifles could no longer be effective against anything but light tanks; any rifle made powerful enough for heavier tanks would exceed the ability of a soldier to carry and fire the weapon. Even with the first tanks, artillery officers often used field guns depressed to fire directly at armored targets. However, this practice expended much valuable ammunition and was of increasingly limited effectiveness as tank armor became thicker. The first dedicated anti-tank artillery began appearing in the 1920s, and by World War II was a common appearance in most armies. In order to penetrate armor they fired specialized ammunition from proportionally longer barrels to achieve a higher muzzle velocity than field guns. Most anti-tank guns were developed in the 1930s as improvements in tanks were noted, and nearly every major arms manufacturer produced one type or another. Anti-tank guns deployed during World War II were manned by specialist infantry rather than artillery crews, and issued to infantry units accordingly. The anti-tank guns of the 1930s were of small caliber; nearly all major armies possessing them used ammunition, except for the British Army, which had developed the Ordnance QF 2-pounder. As World War II progressed, the appearance of heavier tanks rendered these weapons obsolete and anti-tank guns likewise began firing larger calibre and more effective armor-piercing shells. Although a number of large caliber guns were developed during the war that were capable of knocking out the most heavily armored tanks, they proved slow to set up and difficult to conceal. The latter generation of low-recoil anti-tank weapons, which allowed projectiles the size of an artillery shell to be fired from a man's shoulder, was considered a far more viable option for arming infantrymen. First shaped charge, portable weapons , a forerunner of modern-day RPGs The RPG has its roots in the 20th century with the early development of the explosive shaped charge, in which the explosive is made with a conical hollow, which concentrates its power on the impact point. Before the adoption of the shaped charge, anti-tank guns and tank guns relied primarily on kinetic energy of metal projectiles to defeat armor. Soldier-carried anti-tank rifles such as the Boys anti-tank rifle could be used against lightly-armored tankettes and light armored vehicles. However, as tank armor increased in thickness and effectiveness, the anti-tank guns needed to defeat them became increasingly heavy, cumbersome and expensive. During WW II, as tank armor got thicker, larger calibre anti-tank guns were developed to defeat this thicker armor. While larger anti-tank guns were more effective, their weight meant that they increasingly were mounted on wheeled, towed platforms. This meant that if the infantry was on foot, they might not have access to these wheeled, vehicle-towed anti-tank guns. This led to situations where infantry could find themselves defenseless against tanks and unable to attack tanks. Armies found that they needed to give infantry a human-portable (i.e., carried by one soldier) weapon to defeat enemy armor when no wheeled anti-tank guns were available, since anti-tank rifles were no longer effective. Initial attempts to put such weapons in the hands of the infantry resulted in weapons like the Soviet RPG-40 "blast effect" hand grenade (where "RPG" stood for ruchnaya protivotankovaya granata, meaning hand-held anti-tank grenade). However, being hand thrown weapons, they still had to be deployed at suicidally close range to be effective. What was needed was a means of delivering the shaped charge warhead from a distance. Different approaches to this goal would lead to the anti-tank spigot mortar, the recoilless rifle, and, from the development of practical rocketry, the RPG. Research occasioned by World War II produced such weapons as the American bazooka, British/Allied PIAT and German Panzerfaust, which combined portability with effectiveness against armored vehicles, such as tanks. The Soviet-developed RPG-7 is the most widely distributed, recognizable and used RPG in the world. The basic design of this RPG was developed by the Soviets shortly after World War II in the form of the RPG-2, which is similar in function to the bazooka (due to the reloadability) and the Panzerfaust (due to an oversized grenade that protrudes outside of a smaller launch tube and the recoilless launch), though the rounds it fires lack a form of propulsion in addition to the launch charge (unlike the RPG-7 rounds, which also feature a sustainer motor, effectively making the rounds rocket propelled grenades). Soviet RPGs were used extensively during the Vietnam War (by the Vietnam People's Army and Vietcong), as well as during the Soviet invasion of Afghanistan by the Mujahideen and against South Africans in Angola and Namibia (formerly South West Africa) by SWAPO guerillas during what the South Africans called the South African Border War. In the 2000s, they were still being used widely in conflict areas such as Chechnya, Iraq, and Sri Lanka. Militants have also used RPGs against helicopters: Taliban fighters shot down U.S. CH-47 Chinook helicopters in June 2005 and August 2011; and Somali militiamen shot down two U.S. UH-60 Black Hawk helicopters during the Battle of Mogadishu in 1993. RPGs were used by militants to destroy "hundreds" of vehicles (AFVs, armored Humvees etc) in the War in Afghanistan (2001–2021). ==Design==