The U.S. Marine Corps sees the 120mm Expeditionary Fire Support System (EFSS) mortar as the 3rd leg of its expeditionary fire support triad. EFSS will be the short-range but easily transportable counterpart to the reduced-weight M777 155mm towed howitzer, and the truck-mounted M142 HIMARS rocket system.
Accompanying Marine Air Ground Task Forces (MAGTFs) in expeditionary operations, EFSS will be the heliborne Ship-To-Objective Maneuver (STOM) force’s primary fire support, before the larger and longer range systems can move into position. As such, the EFSS launcher, its Internally Transportable Vehicle (ITV) carrier, a portion of the basic load of ammunition, and a portion of its crew, must all be transportable by a single CH-53E Super Stallion or future CH-53K heavy lift helicopter, and/or a single MV-22 Osprey tilt-rotor aircraft. The program’s path has not been smooth, and its vehicle choice in particular has come in for criticism, as it heads toward full-rate production.