When the German Army (and its allies) turned its attention to the Soviet Union in June of 1941 to begin "Operation Barbarossa", the Soviets were ill-equipped to deal with the strength of the "blitzkrieg". Furthermore, their anti-tank measures were wholly inadequate against the surge of Axis armor incoming that, along with a few anti-tank rifles, several anti-tank grenade measures were hurriedly implemented. The first of the notable types became the "RPG-40" ("Ruchnaya Protivotankovaya Granata Model of 1940") with its identifiable "stick" grenade shape mimicking the German Model 1924 line to an extent. The RPG-40 proved sufficient against the early German Panzer tank offerings thanks to a capable TNT warhead but these weapons also proved heavy at 2.5lbs and cumbersome to wield with equated to short throwing distances. Size also limited how many an operator could effectively carry.
The Soviet strategy utilizing RPG-40s was forced to evolve with the arrival of the Panzer IV and heavier Panzer V "Panther" and "Tiger I" models. This prompted the design, development and adoption of yet another anti-tank grenade type which became the "RPG-43" series of 1943. The weapon was given a shaped charge warhead with impact fuse detonation and could counter 3" armor thickness. Again, the design adopted a stick grenade shape, weighed over 2lbs and proved effective if not still cumbersome. Regardless, the type served a need and proved its worth in the heat of battle, remaining as a standard issue infantry-level anti-tank weapon throughout the war.
Beyond its weight - which limited throwing ranges as in the RPG-40 before it - the RPG-43 also relied on its impact fuse for detonation which required a good amount of force to actuate. The grenade also required its approach to be roughly 90-degrees against the armor surface for true effectiveness. As improvements could be made, they were - and this begat the "RPG-6" which soon joined the line in 1943.
The RPG-6 continued the general stick grenade shape which included the holding handle and warhead, all covered in sheet metal. A pin and lever ensured safety and manual actuation. The warhead was given an all-new shape for improved penetration values when compared to previous RPG iterations. Stability in flight - for when the grenade was thrown - was managed through four fabric tails. The RPG-6 went on to see extensive combat service in the war for not only its armor-defeating value but also as an anti-personnel weapon for its stellar fragmentation effects upon detonation. Its value was such that many were still in use during the early Cold War years and exported to Soviet supported and aligned nations and states. It saw extended use in the Middle East during the 1948 Arab Israeli War, the 1967 Six Day War and Yom Kippur of 1973.
Operators included Albania, Algeria, Bulgaria, Czechoslovakia, East Germany, Egypt, Syria, Hungary, Iraq, Israel, Jordan, Libya, Morocco, Poland, Romania, Saudi Arabia, Sudan Tunisia and Yemen.