New U.S. 60mm Mortar

photo Adrian Muehe

July 26, 2011: STRATEGY PAGE

U.S. Army troops have finally begun receiving the new M224 lightweight 60mm mortar. Weighing 16.1-21.1 kg (35.4-47 pounds), the new weapon is a much awaited improvement on older models.  For ease of carrying the mortar breaks down into several components. The tube weighs 6.5 kg (14.4 pounds), the bipod is 6.9 kg (15.2 pounds) and the sight is 1.1 kg (2.5 pounds). There are two base plates. The standard one is 6.5 kg (14.4 pounds), the lightweight one is 1.6 kg (3.6 pounds). The older World War II era M2 model weighed 19.05 kg (42 pounds). The less successful World War II era M19 weighed 23.4 kg (52 pounds).

Some of the M224 technology arrived early. Three years ago a new mortar tube was introduced for the 60mm and 81mm mortars. New metals (Inconel 718 alloy) and manufacturing methods (flowforming) reduced the weight of theses mortar tubes 30 percent, and increased the robustness. But rhe lighter tube only reduced the overall system weight about ten percent.

For the infantry, however, every pound counts. The U.S. Marines also bought some of the lightweight 60mm and 81mm tubes. But the marines were particularly keen to see how the lighter M224 60mm version works, which uses the new tube.

The marines and the army use the 60mm for infantry companies, giving the company commander his own artillery. Modern 60mm mortar shells, which weigh about 1.6 kg (3.5 pounds) each, have a range of 2,000-3,500 meters.  For many decades, the max range of 60mm mortars was more like 2,000 meters. The longer range shells, and the availability of mini-UAVs at the company level, make the 60mm mortar a much more potent weapon. The UAV can spot targets behind hills or buildings, and then adjust the mortar fire until the target is destroyed.

Infantry mortars were invented during World War I (1914-18), but have been largely unchanged since then. The current U.S. mortar designs were introduced in the 1980s, but the new tube, longer range ammo, and guided shells (in larger calibers than 60mm) are rather recent developments.