MOS 0311 is a Military Occupational Specialty (MOS) code used by the United States Marine Corps (USMC) to identify the role of an Infantry Rifleman. It is one of the most fundamental and numerous infantry MOSs within the Marine Corps, representing the core combat role.
The Infantry Rifleman is primarily responsible for locating, closing with, and destroying the enemy by fire and maneuver, or repelling enemy assault by fire and close combat. This role is central to the Marine Corps' identity as an expeditionary fighting force.
Responsibilities of an MOS 0311 include, but are not limited to:
- Operating various small arms, including rifles, carbines, machine guns, and grenade launchers.
- Employing hand grenades and other explosive devices.
- Conducting tactical movements, patrols, and reconnaissance.
- Executing offensive and defensive combat operations.
- Maintaining and cleaning assigned weapons and equipment.
- Operating as part of a fire team, squad, or platoon in diverse environments.
- Participating in physical training to maintain combat readiness.
Marines holding the 0311 MOS typically serve in rifle platoons within infantry battalions, which are the backbone of the Marine Air-Ground Task Force (MAGTF). Their training emphasizes marksmanship, land navigation, close-quarters combat, patrolling, and field craft.
While 0311 is a specific entry-level infantry MOS, Marines may advance to other infantry-related MOSs (e.g., 0321 Reconnaissance Marine, 0331 Machine Gunner, 0341 Mortarman, 0352 Anti-Tank Missileman) or leadership roles (e.g., Squad Leader, Platoon Sergeant) after gaining experience and undergoing further specialized training.