Till reading a book about German paratrooper this year I did not know that it was used by the German & American paratroopers in WW II The first recoilless rifle to enter service in Germany was the 7,5 cm Leicht Geschütz 40 ("light gun" '40), a simple 75 mm smoothbore recoilless gun developed to give German airborne troops some useful artillery and anti-tank support that could be parachuted into battle. The 75 was found to be so useful during the invasion of Crete that a larger 105 mm version was developed on the same basic pattern. Interestingly both of these weapons were loosely copied by the US Army, reversing the flow of technology that had occurred when the Germans copied the Bazooka. The US did have a development program and it is not clear to what extent the design was copied, as there were in fact differences. The Japanese had also developed a portable recoilless anti-tank rifle which they had reserved for the defense of anticipated invasion of the mainland. As it was, however, these weapons remained fairly rare during the war though the US versions of the 75 started becoming increasingly common in 1945.