The BM-21K Grad artillery rocket system was developed in Ukraine to replace the ageing Soviet BM-21 Grad. Its development commenced in 2001 to meet requirements of the Ukrainian MoD, however due to funding problems development continued as a private venture. First prototype was completed in 2009. The BM-21K was the first multiple launch rocket system, developed in Ukraine. This MLRS is in service with Ukrainian Army. The BM-21K was proposed for possible export customers, however it received no production orders.

   The BM-21K is similar to its predecessor. It has 40 launching tubes for 122 mm artillery rockets. It is compatible with all rockets, developed for the BM-21 Grad, as well as newly-developed rockets. A standard HE-FRAG rocket is 2.87 m long and weights 66 kg. The BM-21K can also fire new extended-range rocket with cluster or HE-FRAG warheads. Maximum range of fire is up to 40 km with extended-range rockets.

   The previous Ural-375D truck out dated and its engine was thirsty on petrol. Vehicle was replaced with Ukrainian-built KrAZ-260 heavy utility truck powered by a more powerful and fuel efficient diesel engine. Also the KrAZ-260 truck offers nearly twice more payload.

   Also the KrAZ truck has a longer cargo platform. Extra space was used to mount a double-cab for the crew. It is worth mentioning, that on the old Soviet BM-21 Grad in traveling order two crew members were carried on the opened platform behind the cab without any cover. However it seems that Ukrainian Army only operates the BM-21K artillery rocket systems with a single cab. This version is called Bastion-1 and has been deployed during the recent military conflict in Ukraine.

   The BM-21K is fitted with GPS, which is used both for navigation and targeting. At a maximum range of 40 km rockets have a CEP of only 90 m.

   Vehicle is powered by a YaMZ-238 turbocharged diesel engine, developing 240 hp. It was also proposed with a YaMZ-238L diesel, developing 300 hp. The launcher vehicle has considerable cross-country mobility.

   A battery of BM-21K Grads includes launching vehicles, command vehicle and ammunition resupply vehicles. The rocket launcher is reloaded manually by the crew within 7 minutes.

   With the introduction of the BM-21K production of the KrAZ-260 truck ceased and it was replaced by the new KrAZ-6322 heavy utility truck. So the multiple launch rocket system was redeveloped and based on the new truck. The new version was designated as the BM-21U, but is also referred as Bastion-1.