The Browning Automatic Rifle

Battalion: An Organizational Study of United States Infantry

The estate of the late John Sayen has graciously given the Tactical Notebook permission to serialize his study of the organizational evolution of American infantry battalions. The author’s preface, as well as previously posted parts of this book may be found via the following links:

The procurement of new weapons would also have a major impact on the Infantry’s organization. In 1936 the Army officially adopted the M1 Garand semi-automatic rifle. This weapon featured more than twice the rate of fire and nearly the same range and accuracy as the existing M1903 bolt action weapon. However, selection of the M1 raised questions about the future of the Browning Automatic Rifle (BAR) as the Army’s squad automatic weapon. An M1 equipped squad without a BAR could outshoot an M1903 squad with one. The existing version of the BAR was heavy, tended to overheat, and was hard to control in automatic fire. Numerous BARs were in stock, however, and rather than discard them, the Army decided to upgrade them.

The upgraded BAR was called the M1918A2. It had its forearm cut back to ease cooling problems by exposing more of its barrel and gas system to the air. For better controllability in automatic fire it received a cyclic rate reducer that permitted the gunner to select a “fast” rate of 350 rounds per minute for accuracy or an “accelerated” rate of 550 for volume. The bipod on the M1918A2 was moved to a position near the muzzle, counterbalancing muzzle climb. Adding a monopod to the butt permitted the BAR to be clamped onto a specific firing azimuth. A folding butt plate eased the strain that the weapon placed on the gunner’s shoulder. Unfortunately, all these changes increased the BAR’s weight from 15.5 to 23.5 pounds, though this did help to better ballast it for rapid firing.

The resulting improvements in the M1918A2 BAR’s performance were so dramatic that the Army decided to retain the BAR as an interim light machinegun (LMG) at least until the long delayed M1919 Browning was finally ready. Use of the BAR as an LMG forced a change in doctrine as well as in designation. The Army regarded an automatic rifle as just a semi-automatic or automatic rifle that could augment the firepower of a squad’s rifles but was inadequate to serve as the squad’s focus of maneuver in the attack or center of resistance in the defense. Indeed, the Army believed that an unmodified BAR, due to its inaccuracy and tendency to overheat, was not greatly superior to a single M1 rifle.

In contrast to an automatic rifle, an LMG primarily existed to provide fully automatic firepower. It could deliver flanking fire along a fixed azimuth in the defense, or provide a base of fire to support maneuver. It would function similarly to a water-cooled heavy machinegun (HMG) while trading effective range and sustained firepower for better mobility. For the LMG role, the Army considered a tripod mounted belt fed weapon to be capable of delivering about twice the improved BAR’s effective rate of fire. On the other hand, the improved BAR would be much lighter and could be brought into and out of action much faster.¹

Nevertheless, the improved BAR created some important dilemmas. If it was light enough to be a platoon or a squad level weapon, in which role could it best be used? Until 1942, opinion was against putting it back in the rifle squads. A new BAR with a basic ammunition load of ten filled 20-round magazines weighed some 45 pounds. This was not enough to prevent a BAR man from keeping up with riflemen when moving at a walking pace but the BAR man would probably be incapable of the bursts of speed that battle often demanded. Hence, he would tend to lag behind his squad unless it slowed its pace enough to allow him to keep up.

Another problem with a squad-level BAR was that the riflemen, distracted by the need to carry ammunition for and protect the BAR, might fail to exploit the increased firepower of their own M1 rifles. Further, the Army believed that the individualism of the average American would better suit him to fighting as a rifleman rather than as part of a group clustered around an LMG. Naturally, it was recognized that such a philosophy could drive combat formations. A squad whose firepower depended on its rifles would tend to deploy in width, or parallel to the enemy, in order to use as many of its rifles as it could. This would tend to distribute the squad’s manpower and firepower across a relatively broad front, thus complicating tactical control and making it difficult for the squad to focus its efforts in any one place. It might also increase casualties by exposing more squad members to direct enemy fire.

An LMG based squad, on the other hand, could deploy in depth. Since both firepower and maneuver focused on the LMG the LMG crew could be made up of the most reliable and experienced members of the squad. Tactical control would be eased since the squad leader could control the whole squad just by directing the LMG. With the LMG generating much of the squad’s firepower fewer riflemen need be exposed to the enemy. Ultimately, however, the Army decided that the rifle platoon should consist of several all-rifle squads, backed by one or more BAR/LMG squads. The latter would provide a base of fire in the attack and flanking fire in the defense. They could even protect the platoon from air attack. Keeping the LMGs out of the rifle squads would also remove the need to burden those squads with extra men to carry LMG ammunition.²

To modify the existing rifle platoon to incorporate LMGs and M1 rifles while fitting within the framework of a motorized regiment, the Infantry Board reduced the platoon’s six squads to seven men each and dropped a messenger from platoon headquarters, thus cutting the platoon’s enlisted strength to 50. Each rifle section would have two rifle squads and one LMG squad. The LMG squad would have a rifle-armed squad leader, two gunners (armed with BAR/LMG’s), and four ammunition bearers (armed with pistols). The section leader and section guide would also carry rifles along with the platoon sergeant and the three platoon messengers. In the offense, the platoon would operate as before with its two sections in column. Within each section, the LMG squads would lead, probably preceded by scouts. After making contact, the LMGs would fix the enemy with their fire, leaving the riflemen free to maneuver. For the defense, the LMGs would deliver flanking enfilade fire covering the platoon’s frontage. They could function as single guns but would more likely to operate in pairs as two guns could deliver a more continuous fire. Also, one gun could cover for the other should it become disabled.³

Editor’s Note: The format of the many appendices to this work fit poorly with Substack. For that reason, I have placed them on a PDF file that can be found at Military Learning Library, a website that I maintain.

1. The Infantry School “The New Infantry Regiment,” The Infantry School Mailing List Volume XI January 1936 (The US Army Infantry School, Fort Benning Georgia) pp. 4-7; The Infantry School “The Tactics of the New Infantry Rifle Platoon,” The Infantry School Mailing List Volume XI I July 1936 (The US Army Infantry School, Fort Benning Georgia); and Col Lloyd R. Fredendall, Infantry “The Place of the Modified BAR in Organization”, Infantry Journal July 1939 (Washington DC) pp. 334-337.

2. Ibid; and “Notes from the Chief of Infantry - Statement made to the Military Affairs Committee of the House of Representatives” Infantry Journal March-April 1933 (Washington DC) p 141; Brigadier General C. D. Davis “The Infantry Division” Infantry Journal March-April 1936 (Washington DC) p 141; and Major General George A. Lynch, Chief of Infantry “Tactics of the New Infantry Regiment” Infantry Journal March-April 1939 (Washington DC) pp. 102-104. See also “Infantry Digest - The Infantry Regiment-New Style” Infantry Journal Jan 1936 pp. 69-70.

3. The Infantry School “The New Regiment, Tactical Aspects,” The Infantry School Mailing List Volume XI January 1936 (The US Army Infantry School, Fort Benning Georgia) pp. 44-45.