that they needed to give infantry a human-portable (i.e., can be 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 rocket propelled grenade. 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 The RPG warhead being used against tanks and