Marine Corps MOS 0351: Infantry Assault

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The Infantry Assault Marine is on the front line of any infantry mission. The image of unsophisticated "grunts" is an outdated one, however; these Marines use highly advanced weaponry and go through intensive training before leading the way into battle.

Categorized as a military occupational specialty (MOS) 0351, Infantry Assault Marines (formerly Infantry Assaultmen) are, as the name implies, found in the assault section of Marine weapons platoons of infantry rifle companies. Like other combat infantry jobs, MOS 0351 has been open to women since 2015.


Infantry Assault Marines use several weapons as part of their jobs, including rockets and Anti-Personnel Obstacle Breaching Systems (APOBS). Their duties include providing rocket fire in support of rifle squads, platoons, and other companies within the infantry battalion.

These Marines will use breaching and infiltration techniques when the infantry is on the offensive and employ demolition and other countermeasures when in a defensive position. Noncommissioned officers in this job are usually assigned as gunners or a team, squad and section leaders.


As with many Marine infantry jobs, where you attend recruit training will determine which infantry school you will attend as MOS 0351. Marines on the East Coast will attend infantry training school at Camp Geiger near Camp Lejeune in Jacksonville, Noth Carolina. After this training, Marines go on to training at Parris Island. The west coast school of infantry is at Marine Corps Recruit Depot in San Diego at Camp Pendleton.

There are two separate schools within the School of Infantry: Infantry Training Battalion and Marine Combat Training.


Specialties in the USMC Infantry Company (three rifle platoons and one weapons platoon) include:

  • Rifleman: Trained in close combat, operates M4, M203 Grenade Launcher, and the M249 Squad Automatic Weapon.
  • Machine Gunner: Employs medium and heavy machine guns in support of maneuver elements.
  • Mortar Marine: Provides indirect fire in support of maneuver elements using light, medium or heavy mortars
  • Assault Marine: Assaults fortified targets with rockets, demolitions, and breaching/infiltration techniques.


Marines in this job will need a General Technical (GT) score of 100 or higher on the Armed Services Vocational Aptitude Battery (ASVAB) test. They’ll need normal color vision (no color blindness) and vision of 20/200 correctable to 20/20.

Becoming a Marine

Marine infantry training is among the most grueling in the U.S. Armed Forces. New Marines train for 59 days to learn how to "fight, service and win in combat." This training includes, among other things, combat marksmanship instruction, how to detect IEDs (improvised explosive devices), and how to use grenades in combat. 

Depending on which MOS they're entering, the next phase of this Marine boot camp could include anything from instruction in machine guns and mortars to anti-tank warfare techniques.

The physical training portion of Marine infantry training is where many who aren't cut out for this branch of the service figure it out. Being a Marine is definitely not for the faint of heart, and being an infantry Marine requires serious fortitude and resilience.