March 30, 2012: China has produced an improved Russian 122mm (BM-21, also known as Grad or Katyusha) rocket. The original was introduced during World War II and has been a favorite ever since. The new Chinese PR50 system uses a 122mm rocket that weighs 74 kg (163 pounds), is 2.9 meters (nine feet) long, and has a 21.5 kg (47.3 pound) warhead. Minimum range is 20 kilometers, max range is 40 kilometers. The PR50 is actually a complete system, including a truck mounted launcher that holds two 40 rocket launcher boxes. The truck has an automated aiming and reloading system. The PR50 rocket is interchangeable with the older BM-21 type rockets.

The 122mm BM-21s weigh 68.2 kg (150 pounds), are 2.9 meters (nine feet) long, and have a 20.5 kg (45 pound) warhead. The BM-21 rockets have a maximum range of 20 kilometers. Again, because they are unguided, they are only effective if fired in salvos or at large targets (like cities, large military bases, or large groups of troops or vehicles on the battlefield). There are Egyptian and Chinese variants that have smaller warheads and larger rocket motors, giving them a range of about 40 kilometers.

BM-21 was introduced in 1962 and replaced the World War II era BM-13 132mm rocket. This weapon entered service in 1939, weighed 23 kg (50 pounds), was 600mm (24 inches) long, had a 4.9 kg (15 pound) warhead, and a max range of 11.8 kilometers. The BM-21 was a big improvement. As can be seen with the PR50, the original BM-21 design is hard to completely replace.