 During the early days of Operation Barbarossa, the USSR's only infantry anti-armour weapons were anti-tank rifles, anti-tank guns, and anti-tank hand grenades.These were adequate against early German tanks such as the Panzer I and Panzer II but, as the war progressed, they were found to be nearly useless against the heavier Panthers and Tigers.The RPG-43 was developed as a result, and it was produced in large numbers until the end of the war.