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Military Organization > United States > U.S. Marine Rifle Platoon (Planned)

U.S. Marine Rifle Platoon (Planned) 

The following will be the organization of the U.S. Marine Corps Rifle Platoon following reorganization planned for the 2020s. These changes were announced in 2018 on the heels of the replacement of the M4 Carbine with the M27 IAR in rifle squads.

This is an updated article as we first reported on the changes announced in May 2018 that called for the reduction of squad strength to 12 men each. A few months later this was changed to an increase to 15 men each.


  1. Organization

  2. Discussion

  3. Sources

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      Organization      ​​

  • Type: Marine Infantry Platoon

  • Origin: U.S. Marine Corps (United States)

  • Personnel: 1 Officer and 47 Enlisted and 1-3 Usual Enlisted Attachments

​→ Platoon Headquarters (1 Officer and 2 Enlisted + 1-3 Attachments)

  • 1× Platoon Commander, Second Lieutenant or First Lieutenant (OF-1), armed with 1 M27 IAR

  • 1× Platoon Sergeant, Staff Sergeant (OR-6), armed with 1 M27 IAR

  • 1× Radiotelephone Operator (RTO), Lance Corporal (OR-3), armed with 1 M27 IAR

  • 1-3× Corpsmen*, Hospitalman or Petty Officer, armed with 1 M27 IAR

* Corpsmen are a U.S. Navy sailor attached to the rifle platoons as combat medics.

​→ 3× Rifle Squads (15 Enlisted Each)

  • 1× Squad Leader*, Sergeant (OR-5), armed with 1 M27 IAR

  • 1× Assistant Squad Leader, Corporal (OR-4), armed with 1 M27 IAR

  • 1× Squad Systems Operator, Lance Corporal (OR-3), armed with 1 M27 IAR

  • 3× Fire Teams

    • 1× Team Leader, Corporal (OR-4), armed with 1 M27 IAR

    • 1× Automatic Rifleman, Lance Corporal (OR-3), armed with 1 M27 IAR

    • 1× Grenadier, Lance Corporal (OR-3), armed with 1 M27 IAR and 1 M320 40mm grenade launcher (standalone)

    • 1× Rifleman, Lance Corporal (OR-3)

      • One fire team's Rifleman will be armed with an M38 SDMR​

      • One fire team's Rifleman will be armed with an M27 IAR and M3E1 MAAWS (Carl Gustaf)

      • One fire team's Rifleman will be armed with an M27 IAR

* The most senior squad leader acts as assistant platoon sergeant. Under the TO&E the platoon guide takes on this role, although in reality the dedicated platoon guide role is not often used.


      Discussion      ​​

The U.S. Marine Corps' Rifle Platoon consists of a platoon headquarters and 3 rifle squads. This amounts to 1 officer and 47 permanent enlisted personnel, as well as 1-3 directly attached enlisted personnel. This does not include weapons teams (M240, Javelin) that are usually attached to the platoons from the company weapons platoon or battalion weapons company to increase their firepower.

The Platoon Headquarters consists of a platoon commander (Second or First Lieutenant), platoon sergeant (Staff Sergeant), and radiotelephone operator/RTO (Lance Corporal). Additionally, 1-3 Corpsmen are typically attached to the platoon in combat operations. Corpsmen are Navy personnel that fill the role of combat medics when attached to Marine units. It has been confirmed that the platoon headquarters - including the Corpsmen - will be armed with M27s.

Each Rifle Squad consists of 15 enlisted personnel. Its basic subdivisions are the squad headquarters and 3 homogeneous fire teams. The squad headquarters consists of a squad leader (Sergeant), assistant squad leader (Corporal), and squad systems operator (Lance Corporal). The addition of the assistant squad leader improves workload management for the squad and command and control, with the squad leader able to delegate certain tasks to the assistant squad leader. With the rifle squad's 3 fire teams and the frequent attachment of M240 machine gun teams teams, Marine squads leaders can often be in the position of having to command 5 subunits (3 fire teams and 2 attachments). For comparison, the U.S. Army squad leader typically only commands 2 fire team leaders before the addition of any M240 or Javelin teams. The assistant squad leader was last a part of the Marine rifle squad prior to the 1944 reorganization, where that billet was replaced by the fire team leaders. The squad systems operator gives the squad a light quadcopter drone capability, which can provide limited reconnaissance. This is a force multiplier, as it gives individual squads the capability of scouting ahead. An example of added capability would be the ability to spot things like hidden ambushes before they enter a killzone.


Each fire team consists of a fire team leader (Corporal), automatic rifleman (Lance Corporal), grenadier (Lance Corporal), and rifleman (Lance Corporal). The grenadier operates standalone M320 launchers - a weapon that the U.S. Army started employing primarily in an underbarrel configuration several years ago. The automatic rifleman operates the M27 IAR in the role of automatic rifle, although because the rest of the team are also armed with it they can trade off that role for fire and maneuver purposes. The rifleman of one of the fire teams will be armed with an M38 Squad Designated Marksman Rifle, while another will be armed with the M3E1 MAAWS. The third fire team's rifleman will be just armed with an M27 IAR.


It should be noted that in practice, fire team leaders are often senior Lance Corporals, due to a shortage of Corporals. Further, Lance Corporal billets are likely to be filled by Privates and Private First Classes as well. Although Marines who graduate recruit training as Private First Classes can often enter the fleet as Lance Corporals (only one Marine per recruit company may graduate as a Lance Corporal) and most will reach the rank of Lance Corporal, this is entirely dependent on how long a squad's members have been in the Marine Corps.

As far as structure is concerned, this is the first major change to the squad organization since World War II. Since 1944, the squad has consisted of 3 fire teams of 4 men each and a squad leader. There was a brief aside during the Vietnam War when a dedicated grenadier armed with the M79 "thumper" was at the squad headquarters. Otherwise, the Marine Corps rifle squad has been 13 men with 3 4-man fire teams based around an automatic rifleman. Sometimes more than others the distinction between automatic rifleman has been more on paper than based in reality. This was the case during Vietnam, when the adoption of the M16A1 and the removal of the M14A1 from the squad left it without a dedicated automatic rifle until the adoption of the M249 SAW in the 1980s. That distinction is being blurred again with every member of the squad being armed with the same M27 (this will be discussed more in the "Weapons" section).


Summary of Changes

  • The rifle squad size was increased from 13 men to 15 men. The assistant automatic rifleman billet was removed from the fire teams, while the grenadier billet was added to the fire teams. The assistant squad leader and squad systems operator billets were added to the squad headquarters.

  • The M4 Carbine was replaced by the M27 IAR as the platoon's standard service weapon.

  • The M3E1 MAAWS and M38 SDMR was made available to each rifle squad.



The primary service weapon of the U.S. Marine Corps' rifle platoons will be the M27 IAR. The M27 is a variant of the Heckler & Koch HK416, an AR15-based 5.56x45mm NATO assault rifle. The HK416 differs from other ARs - including the M16 and M4 - in that it uses a short-stroke piston gas system rather than pseudo-direct impingement (contrary to popular belief, the AR system isn't truly direct impingement as there is a small piston on the bolt carrier that the gas acts on). This change theoretically increases the reliability, decreases malfunctions, and increases the service life of the system. In addition to the Marine Corps, the Norwegians and French have adopted the HK416 as their standard service rifles and it is currently in use by numerous other special forces and law enforcement organizations.


The M27 was initially adopted in 2011 in replacement of the M249 SAW. The M249 was relegated to the company weapons platoon. Each rifle company maintains a stock of 6 M249s, which would be enough to equip each platoon with 2 M249s. The rationale - aside from possibly being a Trojan horse to fast track the adoption of a new service rifle - is that precise fire from a lighter (less fatiguing) automatic rifle offsets the volume of fire offered by a belt-fed light machine gun like the M249 as far as suppression is concerned. Although the Army has chosen not to adopt the M27 in a similar role, the weight of the M249 is an issue to them as well, as they are currently testing a lighter SAW chambered in a caseless 6.8mm round. However, with the M27's initial adoption as an M249 replacement, it was merely a one-for-one replacement with no structural change. It was announced in late 2017 that the M27 would be replacing the M4 as the standard service weapon for the infantry, and the organizational changes detailed herein were announced in 2018. All squad members armed with the same weapon mirrors the Marine Corps' situation in the later half of Vietnam, where all members of the squad (with the exception of the M79 grenadier) were armed with the M16A1.

As with the Marine rifle squad organization during Vietnam, the automatic rifleman is armed with the same rifle as everyone else. The automatic rifleman is differentiated mostly by being designated to use automatic fire and carrying more ammunition. The standard ammunition carriage is 1,980 rounds specifically for the automatic rifleman split across 22 30-round magazines, although 40-round and 60-round magazines are being tested. This compares to the typical 3 200-round belts, or 1,800 rounds per fire team, that were standard with the M249 (depending on the mission). However, one key difference is that the M27 IAR is better equipped for automatic fire than the M16A1 was. The potential flexibility in having any squad/fire member being able to provide automatic fire, trade off when the automatic rifleman is reloading, and not having all of the team's automatic fire capacity concentrated in one SAW gunner could be possible advantages that offset the loss of the volume of sustained fire that a belt-fed M249 offered. Additionally, credence has been given to the concept of precision over volume in regard to suppression. The M27 IAR is a far more accurate weapon than the M249, as well as the M4, which plays into the Marine Corps' focus on marksmanship. This concept has not been accepted by the U.S. Army, however, as rather than adopting the M27 or a similar automatic rifle they are currently experimenting with light, belt-fed, cased telescoping ammunition light machine guns to replace the M249.

Additionally, the Marine Corps is considering the adoption of a "squad common optic" that is capable of switching between 1x and 6-8x magnification. Whether this will materialize as an optic that can switch between 1 low magnification and 1 high magnification setting, or a variable optic where one can get a magnification in between has not yet been confirmed. Currently, the standard optics on rifles are the Trijicon TA11 (3.5x magnification squad day optic) and TA31 (4x magnification rifle combat optic) ACOG, although the TA11 started being replaced in infantry units beginning in 2016. Meanwhile, the M38 SDMR, or squad designated marksman rifle (essentially an M27 with a more powerful optic and suppressor), is ideally equipped with a Leupold Mark 4 M3 with variable 3-9x magnification. A replacement could unify the optics of the squad, giving every member the capability of fulfilling the roles of rifleman, automatic rifleman, and designated marksman on paper.

The squad's underbarrel-mounted M203 40mm grenade launchers are also being replaced by the M320 40mm grenade launcher - a variant of the Heckler and Koch AG36. However, unlike the M203 in Marine service, the M320 will be deployed primarily as a standalone weapon rather than as an attachment. As such, there will be a dedicated grenadier, whereas prior each fire team leader had been armed with the M203. It appears that M27s are arriving at units before M320s. In units that have not received M320s, M4 carbines will be retained for the utility of the M203. As of 2019, the squad structure has not been altered. As it is not expected that all units will be fully outfitted with M27s until the mid-2020s, it is uncertain when all the changes will actually be rolled out although the Marine Corps hopes to start by 2020.

Additionally, 1 M3E1 Multi-Role Anti-Armor Anti-Personnel Weapons System "MAAWS" will be issued 1 per rifle squad. The MAAWS is a variant of the Swedish M3 Carl Gustaf 84mm recoilless rifle, and is intended to eventually replace the Mk 153 SMAW currently in service with rifle company weapons platoons. The Commandant has stated that the assaultman MOS (which serves SMAWs in the weapons platoon) will be done away with, to be replaced by other members of the rifle company (presumably the squad level MAAWS). It was estimated that this would take until 2022 to happen when reported in 2018.


      Sources      ​​

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