The BM-21 "Grad" () is a self-propelled 122 mm multiple rocket launcher designed in the Soviet Union. The 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. BM stands for boyevaya mashina ( – combat vehicle), and the nickname means "hail". The complete system with the BM-21 launch vehicle and the M-21OF rocket is designated as the M-21 field-rocket system. The complete system is more commonly known as a Grad multiple rocket launcher system.
In NATO countries the system, either the complete system or the launch vehicle only, was initially known as the M1964. Several other countries have copied the Grad or have developed similar systems. In Russian service its intended replacement is the 9A52-4 Tornado. Many similar 122 mm MLRS systems are made by different countries based on the BM-21 Grad.
Description
The M-21 field rocket system with a BM-21 launch vehicle (122 mm multiple rocket launcher (MRL) system) entered service with the Soviet Army in 1963 to replace the aging 140 mm BM-14 system. The launch vehicle consists of a Ural-375D 6x6 truck chassis fitted with a bank of 40 launch tubes arranged in a rectangular shape that can be turned away from the unprotected cab.
The vehicle is powered by a water-cooled V8 180 hp gasoline engine, has a maximum road speed of , a road range of up to , and can cross fords up to deep. The original vehicle together with supporting equipment (including the resupply truck 9T254 with 60 rockets) is referred to by the GRAU index "9K51". The launcher itself has the industrial index of "2B5". In 1976, the BM-21 was mounted on the newer Ural-4320 6x6 army truck.
The three-member crew can emplace the system and have it ready to fire in three minutes. The crew can fire the rockets from the cab or from a trigger at the end of a cable. All 40 rockets can be away in as little as 20 seconds, and can be fired individually or in small groups in several-second intervals. A PG-1M panoramic telescope with a K-1 collimator can be used for sighting.
Each rocket is slowly spun by rifling in its tube as it exits, which along with its primary fin stabilization keeps it on course. Rockets armed with high explosive-fragmentation, incendiary, or chemical warheads can be fired . Newer high explosive and cargo rockets (used to deliver anti-personnel or antitank mines) have a range of and more. Warheads weigh around , depending on the type.
The number of rockets that each vehicle is able to quickly bring to bear on an enemy target makes it effective, especially at shorter ranges. One battalion of eighteen launchers is able to deliver 720 rockets in a single volley. The system has lower precision than gun artillery and cannot be used in situations that call for pinpoint accuracy. It relies on a large number of shells dissipating over an area for a certain hit rate on specific targets. Because of the short warning time for the impact of the whole volley, the BM-21 is still considered an effective weapon.
Variants
Russia
BM-21: Original version known as the BM-21 launch vehicle. The launcher unit was mounted on a modified Ural-375D truck chassis. BM-21-1: Launch vehicles are mounted on a family of Ural-4320 truck chassis. 2B17 or also BM-21-1: This upgrade was presented for the first time in 2003 and was developed by Motovilikha Plants from Perm. The system is fitted with a satellite navigation system NAP SNS, automated fire control system ASUNO, APP laying system and can fire a new generation of rockets with a range of . The truck is the Ural-43201.
9P138 "Grad-1": lighter 36-round version, mounted on a 6x6 ZIL-131 chassis. The vehicle with supporting equipment (rockets, transporter 9T450 and resupply truck 9F380) is referred to as complex 9K55. The 9P138 can only use "short-range" rockets with a range of . It used to be known in the West as BM-21b or M1976.
BM-21V "Grad-V" (Vozdushnodesantniy – 'airborne') (NATO designation M1975): Developed for Soviet airborne troops in 1969. A GAZ-66B 4x4 truck chassis is fitted with a 12-round 122 mm rocket launcher. The vehicle is sturdy enough to be air-dropped. Parts of the vehicle such as the canvas cab roof can be taken off or folded down to reduce its size during transit. Like the BM-21, the BM-21V has stabilizing jacks on the rear of the vehicle for support when firing. The launch vehicle has the industrial index of 9P125.
9А51 "Prima": 50-round launcher on a Ural-4320 5t chassis. The vehicle together with fire control equipment, the ammunition transporter TZM 9T232M and the new rocket 9M53F is referred to as complex 9K59. Apparently only a small number was produced.