We’ve looked at the role of the medium machine gun and the heavy machine gun in the US Army. Today, let’s look at the automatic weapon where the boots really hit the dirt- down at the rifle platoon level.
The infantry platoon in WWI was equipped primarily with bolt action rifles. Machine guns like the M1917 and the various light machine guns we used before the M1919 were fixed in place. The infantry platoon had a strange organization. Instead of the familiar squad, there was a headquarters and four sections, divided by the purpose of the soldiers in that section. There were grenadiers who, while they carried a rifle, their main job was lobbing grenades; riflemen; rifle grenademen, who fired grenades off an attachment on their rifles; and automatic riflemen. Now all that was needed was an automatic rifle that could move forward in the assault with the riflemen and grenadiers. At first the Army used a motley collection of foreign made light machine guns, none of which was very satisfactory. Most were too heavy for one man to operate, and all were unreliable.
Again, John Moses Browning, that most successful of American small arms designers stepped up to the plate. Very quickly he designed a fully automatic rifle fed from a 20-round box magazine. His Browning Automatic Rifle was just the light automatic weapon that was needed. It was light enough for one man to carry and fire, while providing a high rate of fire. While it couldn’t provide sustained fire like a heavier weapon, it was able to go to the very front of the lines. It was immediatley placed into production. By the end of the war, most Army units were equipped with it. Each 59-man infantry platoon was equipped with 15 of these hard hitting rifles.
Unlike a machine gun, which would fire from a fixed position to support the troops, the BAR was intended from the start to be used as a rifle, accompanying troops in the assault or adding to the platoons fires in the defense. While the BAR weighed in at almost twenty pounds, it was still light enough for one man to carry and operate.
Soon after the first World War, the Army reorganized the infantry platoon and came up with a more rational, squad based platoon. Now there would be three squads of twelve men each in the platoon. Each squad was lead by a Staff Sergeant with a Sergeant as the assistant squad leader. There were 7 riflemen and a three-man BAR team. The BAR team consisted of the BAR gunner himself, an assistant gunner, who carried extra ammunition and helped the gunner with target identification, and an ammunition bearer who carried even more of the heavy 20-round magazines for the BAR. With this organization, the squad could either assault as a single unit, with fires from the platoon or company providing cover fire; or in a smaller engagement, the BAR team could provide a base of fire while the riflemen of the squad assaulted.
This organization reflected more than just a desire to have automatic weapons at a low level. The US Army is famous for its love of firepower, but what is less appreciated is that has also long been dedicated to mobility and manuever. Having the ability to lay a base of fire at even the squad level reflected the Army’s desire to avoid the static trench warfare of WWI with its horrific casualties and little gain. In the interwar years, the Army knew that to win, it would have to be dedicated to “shoot and scoot.”
The BAR was an effective, if not perfect weapon, and remained in service from WWI until well after the Korean War.
After the Korean War, when the Army moved to adopt the M-14 rifle as its standard, the change to a 7.62mmx51 cartridge made the BAR somewhat superflous. It was thought that the M-14 could be used as an automatic rifle, and while they were all built with the capability for automatic fire, most were locked into a semi-automatic selection (it is this capability to fire on automatic that prevents M-14s from being sold by the Civilian Marksmanship Program, unlike M-1 rifles). Instead, one rifle in each fire team would be used as an automatic rifle. After discovering the M-14 was too light for effective automatic fire, the Army designed a heavier version called the M-15, but then settled on a slightly modified M-14 with a different stock and a bipod as its automatic rifle, the M-14E2.
The M-14E2 was not entirely suitable as a squad automatic weapon either, though. It was still somewhat too light for effective automatic fire with the fairly large 7.62mm round. After more than a two or three round burst of fire, the weapon would have shifted so much from recoil that subsequent rounds would not even come close to the target. Its 20-round magazine and relatively lightweight barrel limited its sustained rate of fire. The Army tried a variety of solutions, including using the M-60 machine gun as a squad automatic weapon, a role it was unsuited for due to its weight and the need for extra ammunition.
When the M-16 with its lightweight 5.56mm round was adopted, the Army thought its search for a squad automatic weapon was over. The M-16 could fire on full auto, and its recoil was light enough for a degree of controllabiltiy. Every man would be an automatic rifleman now. But it soon became apparent that “spray and pray” wasn’t the way to go. Most riflemen were supposed to fire on semiautomatic while the assigned automatic rifleman was given a clip-on bipod to use his M-16 as an automatic weapon. Things stood this way for about 20 years. It wasn’t perfect, but it wasn’t that bad. But still, the same limits on sustained automatic fire that plauged the M-14E2 affected the M-16 as an automatic rifle- a small magazine and lightweight barrel that overheated quickly.
In the late 1970s and early 1980s, the Army searched for a lightweight machine gun or automatic rifle that could be used at the squad level and still provide sustained fires. After looking closely at a great number of weapons, it finally settled on a slightly modified version of the Belgian FN Minimi, a belt fed machine gun in 5.56mm which was itself derived from the FN MAG58 (which, itself slightly modified, would serve in our Army as the M240). The M249 Squad Automatic Weapon entered service in the mid-1980s.
The SAW was relatively lightweight, and could be operated by one man. It was normally fed by a 200-round belt from a plastic container that was attached beneath the weapon. In a pinch, regular 30-round magazines could be used through a port on the left side of the weapon, but this was somewhat unreliable. The 200-round box was unpopular as it tended to fall off the weapon at inoppurtune times and it also rattled when you were trying to move quietly. Many weapons now have cloth 100 or 200-round ammo cases. The weapon has undergone numerous small changes since its entry into service. In addition to the high rate of fire from the belt-fed ammo supply, the weapon has a quick change barrel that can be swapped out when one barrel is overheated. This greatly increases the sustained rate of fire. Each of the two fire teams in a modern rifle squad has a SAW, for a total of six of these light machine guns in a rifle platoon.
Still, the Army is never satisfied (nor are the Marines, who also use the SAW), and is looking for a replacement, probably with a slightly larger bullet, but lighter overall weight. We’ll have to wait and see what comes next.
A note on organizations: I can’t believe that my sharp readers haven’t pointed this out before, but in the previous posts on machine guns, I credited the rifle platoon of WWII with having two M1919 machine guns, and the rifle company with having the M1917. I was wrong. The rifle company had the M1919s, while the battalion heavy weapons company had the M1917s. The rifle platoon wouldn’t have its own organic machine guns until after the ROAD reorgainization in the 1950s.