SOTF MISFIT | 0331 Machine Gunner

03xx Infantry / Marine Corps MOS Profile

0331 Machine Gunner

Machine Gunners employ medium and heavy machine guns to support infantry units with suppressive, protective, and sustained fires.

Code / Pipeline0331

MOS NameMachine Gunner

Category03xx Infantry

Unit Association3/5 / 2nd Recon / Force Recon

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Marine Corps MOS Profile

Responsibilities and Pipeline

Primary Responsibilities

Employ Marine Corps machine guns and supervise machine-gun teams and sections.

Training Pipeline

Complete entry-level infantry training and machine gunner instruction.

Billet Progression

This MOS sits inside the Marine ground-combat lane and depends on field discipline, small-unit leadership, communications, weapons proficiency, and repeated field evaluation.

USMC Responsibilities

0331 Machine Gunner is described here by practical Marine Corps duties, billet expectations, and training progression. This section avoids game-language so the page reads like a professional MOS reference.

Employ Marine Corps machine guns and supervise machine-gun teams and sections.
Plan support-by-fire positions, rates of fire, target reference points, ammunition, and gun displacement.
Maintain crew-served weapons, tripods, optics, range cards, and ammunition accountability.
Integrate machine guns with maneuver, fires, and security plans.

Training Pipeline

The pathway is shown at a broad public level. Exact prerequisites, screening, quotas, course names, and assignments can change by fiscal year, manpower requirement, medical qualification, command screening, and schoolhouse policy.

Complete entry-level infantry training and machine gunner instruction.
Serve in weapons platoons, rifle companies, reconnaissance units, or weapons companies.
Develop as assistant gunner, gunner, team leader, section leader, and weapons platoon staff.
Complete advanced infantry and leadership training as assigned.

Billets And Skill Growth

Entry-level Marines focus on core tasks, equipment, field discipline, and reliable execution.
NCOs supervise small teams, enforce standards, plan rehearsals, and train junior Marines.
SNCOs and officers manage readiness, risk, training plans, inspections, reporting, and integration with adjacent staff sections.
Instructor and staff billets preserve standards, document lessons learned, and build repeatable training for the next rotation.

Command Profile Use

Individual names and member-specific history are kept on command profile pages. This MOS page stays focused on the role, standards, training pipeline, and billet use.

Rank / Grade Requirements

Grade LaneEnlisted MOS

Entry / Award Basis

Machine gunner MOS after recruit training and infantry weapons training.

Typical Rank Use

Pvt through Sgt for gunner, team, section, and squad-level weapons billets; SSgt through MGySgt for weapons platoon, company, and infantry operations billets.

Schoolhouse & Qualification Requirements

SchoolhouseSchool of Infantry / Advanced Infantry Training Battalion / Reconnaissance Training Company as applicable

Recruit training, Marine Combat Training or Infantry Marine Course path, then MOS-specific infantry, reconnaissance, scout sniper, weapons, or leader training.

Entry QualificationsScreening / Prerequisites

Must meet infantry screening standards, weapons/field prerequisites, swim or reconnaissance screening where required, medical eligibility, security requirements, and command endorsement for advanced schools.

Associated SchoolsFollow-On Training

Basic Reconnaissance Course / reconnaissance training pipeline when assigned
Basic Airborne Course for parachutist-qualified billets
Military Free-Fall when billet-qualified
Marine Combatant Diver / dive supervisor track when assigned
SERE Level C for designated high-risk or special-operations-associated billets
Scout Sniper / advanced marksmanship schools where applicable

Course titles, quotas, prerequisites, and sequence can change by fiscal year, manpower requirement, medical qualification, and current schoolhouse policy.