BM-21 Grad MRLS Diecast Model. BM-21 Grad MRLS 4" 1.25". BM-21 Grad MRLS. The BM-21 "Grad" is a Soviet truck-mounted 122 mm multiple rocket launcher. The weapons system and the M-21OF rocket were first developed in the early 1960s, and saw their first combat use in March 1969 during the Sino-Soviet border conflict.
