February 1, 2008: The U.S. is
introducing a new mortar tube for its 60mm and 81mm mortars. New metals
(Inconel 718 alloy) and manufacturing methods (flowforming) have reduced the
weight of the mortar tubes 30 percent, and increased the robustness of the
mortar tube. However, that does not result in an enormous decrease in weight.
That's because the entire mortar system consists of three components (tube,
bipod and baseplate) of approximately equal weight (about 15 pounds each for
the 60mm weapon). So the lighter tube only reduces the overall system weight
about ten percent.
For the infantry, however, every pound
counts. The U.S. Marines are buying some of the lightweight 60mm and 81mm
tubes. The marines are particularly keen to see how the lighter M224 60mm
version works. The marines use the 60mm for infantry companies, giving the
company commander his own artillery. Modern 60mm mortar shells, which weigh
about 3.5 pounds each, have a range of 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