Varying reports are coming out of Iraq regarding which types of rocket launchers are on the ground. Some sources report ISIS has taken control of Katyusha rocket launchers; other reports claim sighting M79 Osa and RPG-22 launchers on the ground. It is totally possible that these three varieties of rocket launcher, as well as others, are being used by ISIS forces.
Katyusha rocket launchers are truck mounted launchers that propel multiple rockets towards a target at once. The name Katyusha is a nickname, taken from a song about a woman whose husband is away at war; the song was popular during World War II, when the Katyusha first saw action. The name Katyusha refers broadly to a generation of truck-mounted multiple rocket launchers. Each truck carries between 14 and 48 launchers carrying missiles accurate up to 4,000 yards. Even after the dissolution of the Soviet Union, Russia continued to develop MRL (multiple rocket launchers). Variants on the Katyusha rocket launcher, particularly the BM-21, continue to see action in Russian conflicts, and have recently been spotted in Iraq, Afghanistan, Syria, and Rwanda.