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USMC0331

Machine Gunner

Operates the M240 and M2 heavy machine guns in direct fire support roles. Provides sustained fire support to Marine rifle units in offensive, defensive, and security operations.

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Recruiter vs. Reality
What they tell you

“Master the crew-served weapons systems that provide firepower superiority for Marine infantry units. Operate the M240B and M2 .50 caliber machine gun. Serve as the backbone of infantry squad automatic firepower in every combat environment.”

What it's actually like

The M240 weighs 27.1 pounds. That is not counting the tripod, the T&E mechanism, the ammo, or the existential weight of knowing you are the most conspicuous target on any battlefield because your weapon sounds like the hand of God tearing fabric. You will carry all of this up things that should not be climbed, through things that should not be crossed, in temperatures that should not be experienced by humans. The M2 adds the additional joy of being crew-served by people who will argue for twenty minutes about headspace and timing before admitting they don't remember how to set it correctly. Maintenance on these systems is continuous and non-negotiable. Gunnery ranges are the bright spots. Those moments when the gun runs perfectly and the rounds are going exactly where you want them — that feeling is real and it costs you your lower back. SOI will prepare you for some of this. Nothing fully prepares you for the rest.

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MOS Intel

ClearanceSecret
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PromotionSlow
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Deploy TempoHigh
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BonusVaries by enlistment program
Career Intel
Duty StationsCamp Pendleton (CA) · Camp Lejeune (NC) · MCB Hawaii · 29 Palms (CA) · Okinawa (Japan)
Daily LifeWeapons maintenance, gun drills, range time, and infantry training. Machine gunners are integrated into rifle companies as weapons platoon members. You train to provide suppressive fire, establish engagement areas, and support the maneuver element. Garrison life mirrors standard infantry: PT, maintenance, cleaning, and field exercises.
AIT / SchoolSOI (School of Infantry) at Camp Pendleton or Camp Geiger, followed by the Machine Gunners Course. You learn the M240B and M2 .50 caliber inside and out — assembly, disassembly, maintenance, ballistics, and employment. The course is physically demanding because you carry these heavy systems everywhere.
Physical DemandsExtreme. You carry the M240B (27 lbs) or M2 .50 cal (84 lbs for the system) plus ammunition, tripod, spare barrels, and your standard infantry load. Total pack weight regularly exceeds 100 lbs. Your shoulders, back, and knees will pay the price.
DeploymentsDeploys with infantry battalions on MEU rotations, UDP, and combat deployments; machine gunners are always in demand
Certifications
M240B qualificationM2 .50 cal qualificationMCMAP beltsCombat Lifesaver
Pro Tips
  1. 1Your body is the price of admission. Strengthen your shoulders, back, and legs specifically for load-bearing. A strong 0331 carries the gun effortlessly; a weak one gets crushed.
  2. 2Learn the technical data — range cards, sector sketches, interlocking fires, and final protective fires. The tactical knowledge separates good machine gunners from great ones.
  3. 3Cross-train on the Mk19 automatic grenade launcher and CROWS remote weapon system if available. More weapons quals = more options.
The Honest Truth

Machine gunners are the backbone of the infantry weapons platoon and every rifle company commander wants a good one. The recruiter will tell you it's exciting — and putting rounds downrange with an M2 is genuinely thrilling. What they won't tell you: the weight is no joke. You carry the heaviest weapon system in the platoon on every hump, every patrol, every movement. The physical toll is severe and cumulative. Hearing damage and joint issues are practically guaranteed over a full enlistment. Promotion is as slow as any infantry MOS. The civilian translation is thin — the same challenge as all combat arms. But the discipline, teamwork, and mental toughness you develop are real, and the 0331 community has fierce pride. Just protect your ears and your joints.

Training Pipeline
1
Recruit Training13w
Parris Island (SC) or MCRD San Diego (CA)
2
SOI — ITB8w
Camp Geiger (NC) or Camp Pendleton (CA)
3
Machine Gunner Course3w
Camp Geiger (NC)
M240, M2, Mk19 machine gun employment and crew operations.
On the Outside

What this actually is in the real world

Your skills translate. Here's what civilian employers call this job — and what they pay.

Law Enforcement Officer

Strong match
$66,000$45,000 – $98,000/yr median
Job market: Average

Security Specialist

Related field
$72,000$50,000 – $108,000/yr median
Job market: Average

Defense Contractor

Related field
$95,000$68,000 – $145,000/yr median
Job market: Average
Salary data estimated from BLS Occupational Employment and Wage Statistics and comparable civilian roles. Figures are approximations — use as a guide, not a guarantee.
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What does a 0331 cost the DoD?
$333K 4-year investment — training pipeline, equipment burden, MILPERS breakdown
Follow the Money →
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