#5 – RPG-7
Perhaps the only weapon that has been used as extensively as the AK-47, the RPG-7 is an anti tank shoulder mounted rocket propelled grenade launcher which was first introduced in Russia in 1961 with the official name Ruchnoy Protivotankovyy Granatomyot. It is currently used in over 40 countries and has innumerable variants. Though the US never adopted it on a grand scale, it is currently used by the US forces in Afghanistan for training the military forces. However in recent years it has been more commonly used by irregular militias and terrorist organisations. The latter category include the IRA and the Taliban.