Weapons Company of the Marine Infantry Regiment (28 March 1941)

Battalion: An Organizational Study of United States Infantry

Jul 12, 2023

US Marines examine at 37mm anti-tank gun (1940)

The estate of the late John Sayen has graciously allowed the Tactical Notebook to serialize his study of the organizational evolution of American infantry battalions. Guides to other parts of this (very long) series can be found in the section marked “For Further Reading.”

The “D-series” tables of organization provided each Marine infantry regiment with three infantry battalions, a headquarters and service company, and a regimental weapons company. The last-named unit combined the functions of the anti-tank and cannon companies of contemporary US Army infantry regiments. It consisted of a headquarters, a platoon of 75mm guns, and three anti-tank platoons.

On paper, the 75mm gun platoon was armed with a pair of T12 gun motor carriages. The fruit of the mating of a 75mm field gun with an M3 armored half-track, this was the same weapon that was issued to the 75mm howitzer platoons of many of the cannon companies of contemporary US Army infantry regiments.

However, as few self-propelled 75mm guns reached the Marine Corps before 1943, the 75mm gun platoons of 1941 and 1942 made do with a pair of towed 75mm field guns. (Each of these was a “French 75” of the First World War that had been mounted on a carriage that feature steel wheels, rubber tires, and a split trail.)

Officially designated as “anti-aircraft/anti-tank platoons,” the anti-tank platoons also suffered from the absence of the ordnance with which they were supposed to have been equipped. Thus, rather than employing four 20mm gun dual-purpose guns, each of the anti-tank platoons operated four 37mm anti-tank guns.

Like their counterparts in the Army, the Marine anti-tank platoons consisted of four six-man squads, each of which operated a single gun. Where, however, the Army anti-tank squads were paired off to form sections, the corporals who led Marine anti-tank squads reported directly to the lieutenant who commanded the platoon. The Marine anti-tank platoon also lacked the rifle squads provided to Army anti-tank platoon.