After the success of the BM-13-16 "Katyusha" in 1941, that had 16 rails with 130mm M-13 rockets built on a truck, the need for a larger rocket arose one year later. It saw its debut in the war in 1944 and has been in Forgotten Hope Secret Weapon since version 0.4. This was the BM-31-12 and like the name says, had 12 rails each wit an 300mm M-31 rocket. The rails are actually not made of steel but are just a wooden frame where the rocket is held in place inside the frame. Based on the German Wurfrahmen, they have the nickname Rama. For the Soviets this type of design started with the M-30. But a request for a rocket with a longer distance lead to the M-31 which was based on the M-30. But still, the basic design was the same. The rockets are fired from the Rama. The distance was increased from 2,800 m to 4,325 m with the same 28.9 kg warhead. In March 1944, twelve Rama's were built on a Studebaker US6 chassis which were the first BM-31-12 "Andryusha". This combination proved extremely successful in the later course of war, in particular during the fierce street fightings of Budapest and Berlin.