May 29, 2014:
Israel continues a tradition of developing lightweight 120mm mortars. The latest innovation is the Spear system. This a 120mm mortar that can be mounted on hummer type vehicles. Spear uses an innovative recoil system that reduces the recoil and allows the mortar to be fired from lighter (under six ton) vehicles. The ”soft recoil” system reduces the force of the recoil over 90 percent. The rate of fire is also reduced a bit (from 20 to 16 rounds a minute) but with the use of GPS guided shells this is less of a factor.
This is not the first Israeli lightweight 120mm mortar system. Back in 2004 Israeli innovation in this areas led to the use of a 1.6 ton Israeli mortar in the seven ton Supacat HMT (High Mobility Transport). HMT is four wheel cross country vehicle with a capacity for 3.2 tons. The cab was modified to hold the five man mortar crew. The Israeli mortar system was mounted on a computer controlled turntable. The mortar fired regular 120mm shells 8.2 kilometers, or rocket assisted ones 13 kilometers. This was not as far as a 155mm howitzer can reach, but was adequate to reach targets for the smaller (battalion and brigade) units that used 120mm mortars as their artillery. Air power and rockets were available to handle longer range targets.
The breech loading mortar system allowed for rapid fire and the turntable system takes data directly from forward observers and quickly positioned the 120mm tube to put the shells on the target. This mortar system could put shells on the target within minutes of a request. The system fires 20 rounds in two minutes and uses a GPS assisted fire control system to provide accuracy comparable to any other artillery system. The light weight of this system enabled it to be moved by helicopter or Osprey tilt-wing transport. The Spear mortar follows in this tradition, with the same capabilities of earlier lightweight 120mm mortars but now usable in even lighter vehicles.
The 120mm shells are also about half the weight of 155mm ones. This was overcome with a higher rate of fire and the use of several types of cluster bomb shells and, more recently, GPS guided shells. One of these, for example, will destroy most armored vehicles.
The 120mm mortar is often preferred to 155mm howitzers because the mortar is lighter, faster firing, more mobile and, with the right ammunition, just as destructive as the larger howitzer.