A mortar carrier, also known as a self-propelled mortar, is a self-propelled artillery vehicle carrying a mortar as its primary weapon. Mortar carriers cannot be fired while on the move and some must be dismounted to fire.
In U.S. Army doctrine, mortar carriers are to provide close and immediate indirect fire support for maneuver units while allowing for rapid displacement and quick reaction to the tactical situation. The ability to relocate not only allows fire support to be provided where it is needed faster but also allows these units to avoid counter-battery fire.
Mortar carriers have traditionally avoided direct contact with the enemy. Many units report never using secondary weapons in combat.
Prior to the Iraq War, American 120mm mortar platoons reorganized from six M1064 mortar carriers and two M577 fire direction centers (FDC) to four M1064 and one FDC. The urban environment of Iraq made it difficult to utilize mortars. New technologies such as mortar ballistic computers and communication equipment and are being integrated. Modern era combat is becoming more reliant on direct fire support from mortar carrier machine guns.
- https://www.knox.army.mil/center/armormag/currentissues/2006/ja06/4ward06c.pdfMortar Platoon Training Focus to Meet the Evolving Battlefield