Under the tables of organization of both the G-Series and the J-Series, the machine gun platoon assigned to each rifle company consisted of a modest headquarters and three sections.
Each section fielded a pair of eight-man squads. Thus, with the staff sergeant who served as the section leader, it weighed in at seventeen Marines.
The headquarters employed five Marines - a platoon leader, a platoon sergeant, an ammunition corporal, and two messengers. (Strange to say, the two messengers were the only two men in the entire platoon who rated M-1 rifles. Two men in each squad wore pistols. Every other Marine in the platoon carried an M-1 carbine.)
When a machine gun squad expected to do a lot of movement, it wielded a single machine gun - a tripod-mounted .30-caliber weapon with an air-cooled barrel. When, however, the situation called for additional fire power, the commander of the rifle company enjoyed the option of providing a squad with an additional machine gun. While also a .30-caliber weapon designed in the workshop of John Moses Browning, this second, slightly older, and much heavier, weapon sported a water-cooled barrel.
The division of the machine gun platoon into three sections made it easy for the company commander to attach a machine gun section to each of his three rifle platoons. At the same time, the authors of the tables of organization seem to have imagined this manner of employment - which had been a common practice among rifle companies fighting in jungles during World War II - as a special case. That is, while the machine gun platoon could be employed as a pool of separate sections, they seem to have optimized it for use as an intact unit that, under normal circumstances, would remain under the control of the lieutenant who led it.
To this end, the designers of the machine gun platoon provided the platoon leader with four assistants - two messengers, an ammunition corporal (with a hand-cart of its own), and a platoon sergeant who outranked the leaders of the machine gun sections.
Note on Ranks
Under the G-Series tables, the platoon sergeant of the machine gun platoon ranked as a ‘gunnery sergeant’ and the leader of each section as a ‘sergeant’. Under the establishments of the K-Series, these ranks changed, respectively, to ‘technical sergeant’ and ‘staff sergeant’.
The first alteration resulted from a reform, carried out in 1948, that replaced the cacophony of ranks worn by enlisted Marines during World War II with a simple scheme of seven pay grades, each of which corresponded to a single title. The second shift resulted from a general policy of upgrading the ranks held by enlisted Marines who led small units.
Sources
Weapons: Marine Infantry Battalion (Quantico: Marine Corps Schools, 1942)
‘The New FMF’ The Marine Corps Gazette (May 1947) pages 10-14 (Internet Archive)
‘The FMF Gets a New T/O’ Leatherneck (October 1949) pages 38-39 (Internet Archive)
Ronald R. Van Stockum ‘Machine Guns are Offensive Weapons’ The Marine Corps Gazette (April 1950) pages 50-55 (Internet Archive)
John J. Sayen Battalion: An Organizational Study of United States Infantry (unpublished manuscript) Appendices 5 and 7
For Further Reading
