Migrating Medium Mortars (1938-1945)

Battalion: An Organizational Study of United States Infantry

On 6 June 1938, the US Marine Corps adopted a table of organization for a war strength infantry battalion that, for the very first time, made provision for a platoon armed exclusively with 81mm mortars.¹ In the seven years that followed, the structure of this organization remained essentially the same. In the same era, however, the location of the Marine mortar platoon changed twice. That is, it spent three years in the headquarters company and three years in the weapons company before returning, for the last twenty months of the Second World War, to its original home.

The distribution of 81mm mortars within a mortar platoon

Throughout this period, a Marine mortar platoon consisted of two sections, each of which was armed with a pair of 81mm mortars. The mortar platoon as a whole, therefore, devoted its time and trouble to the care, the movement, the aiming, the firing, and, most of all, the feeding, of four such weapons.

The Marines who served a single mortar formed a ‘mortar squad’. Thus, each mortar section possessed two mortar squads. In addition to this, each section enjoyed the services of a headquarters, which was chiefly concerned with communications, and several ammunition men. (For five years, the ammunition men formed a separate squad. However, the tables of organization approved on 15 April 1943 abolished the separate ammunition section, reduced number of full-time ammunition carriers in each section, and transferred the remaining bomb bearers to the headquarters of the mortar section.)

Number of Marines rated by each mortar section (figure on top of each bar), ammunition squad (red), section headquarters (blue), and mortar squads (green)