Marine Corps · Infantry — crew-served weapons
0331 Machine Gunner VA Disability Claim Guide
The 0331 Machine Gunner carries and employs crew-served weapons — the M240B medium machine gun, the M2 .50-caliber heavy machine gun, and the Mk19 automatic grenade launcher — often as part of a weapons company or a rifle battalion's machine-gun section. This service can help corroborate hazardous-noise exposure and some of the heaviest sustained load carriage in the infantry, but the MOS by itself does not establish a diagnosis or a nexus to a current condition. This guide covers the equipment, the exposures, the records that corroborate them, and common denial patterns for machine-gun claims.
Educational only. A military occupation is not presumptive evidence and does not establish service connection, a diagnosis, or a rating. Last updated 2026-09-06.
What 0331 duty actually involved
Machine-gun sections carry the gun, tripod, T&E mechanism, and hundreds of rounds of linked ammunition in addition to individual equipment, distributing weight across the gun team on foot movements and emplacements. Firing the M240B, M2, and Mk19 from the tripod or a vehicle mount generates sustained, close-proximity impulse noise well above hearing-hazard thresholds, and repeated firing positions from prone and kneeling stances load the shoulders, wrists, and lower back. Gun teams displace frequently to support maneuvering rifle squads, adding repeated setup and breakdown of the tripod system under time pressure.
- Carrying the M240B, M2, or Mk19 plus tripod, T&E mechanism, and linked ammunition on foot movements
- Sustained live-fire employment of crew-served weapons in training and combat, generating high-intensity impulse noise
- Rapid emplacement and displacement of the gun and tripod to support maneuvering infantry
- Repetitive lifting of ammunition cans (each carrying substantial linked-round weight) during resupply
- Vehicle-mounted gunnery, including turret operation with associated vibration and noise
- Field living conditions similar to other infantry MOSs: sleep disruption, weather extremes, and dust
What this occupation may help establish
Each item below supports the in-service event or exposure element only, and only when the veteran's own records back it up.
Sustained high-intensity impulse noise
Crew-served weapons fire — particularly the M2 .50-cal and Mk19 — produces some of the most intense sustained impulse noise in the infantry, and gunners are positioned closest to the muzzle during firing.
Records that corroborate it
- · Hearing-conservation audiograms (DD 2215/2216) and DOEHRS-HC records
- · Range qualification records identifying crew-served weapons courses
- · Fitness reports and Basic Training Record entries documenting machine-gun section assignment
What it does not establish: Documented crew-served weapons exposure supports the noise-event element. A current hearing-loss disability under 38 CFR § 3.385, or a tinnitus complaint, and a medical nexus are still required.
Heavy load carriage
Gun-team loads — weapon, tripod, and ammunition — are among the heaviest individual and team loads carried in the infantry, exceeding the standard rifleman's combat load.
Records that corroborate it
- · Fitness reports describing gun-team or weapons-company assignment
- · Sick call and physical therapy entries for shoulder, back, or knee complaints
- · LIMDU chits and any Physical Evaluation Board records
What it does not establish: That the MOS involves heavy team loads does not by itself establish that a specific joint injury occurred in service.
Repetitive setup, breakdown, and firing-position strain
Frequent tripod emplacement, traversing and elevation adjustments, and prone/kneeling firing positions place repetitive strain on the shoulders, wrists, and lower back.
Records that corroborate it
- · Training schedules and range records showing crew-served weapons courses
- · Sick call entries describing shoulder or wrist complaints
- · Fitness reports referencing field exercises and live-fire ranges
What it does not establish: Repetitive strain typical of the MOS does not establish a current diagnosis of a specific joint condition without clinical findings and a nexus opinion.
Blast and combat-trauma exposure
Machine gunners in weapons companies were frequently attached to maneuvering rifle companies during deployment, exposing them to the same IED and combat-contact risks, though this varies by unit and era.
Records that corroborate it
- · Line-of-duty determinations, after-action reports, and combat award citations
- · Post-Deployment Health Assessment / Reassessment (DD 2796/2900) entries
- · Contemporaneous medical entries describing an altered-consciousness event
What it does not establish: A combat award does not diagnose a traumatic brain injury; residual disability still requires current clinical findings tied to the event.
Deployment-dependent exposures
Burn-pit and other airborne-hazard exposure depends on the specific installation and dates of deployment, not on the machine-gun MOS.
Records that corroborate it
- · Deployment orders and unit deployment histories
- · DD-214 remarks block listing deployments and campaign credit
- · Airborne Hazards and Open Burn Pit Registry participation
What it does not establish: The MOS alone does not establish where a Marine served; presumptive status depends on documented location and dates.
Conditions that commonly arise from these duties
This is not a list of conditions to claim. It is a record-driven view of why the occupation may be relevant and what evidence VA looks at. Only you and your treating providers can identify what you actually have.
| Body system | Condition | Why the occupation matters | Evidence VA weighs |
|---|---|---|---|
| Hearing | Tinnitus | Sustained crew-served weapons fire at close proximity is one of the more intense noise sources in the infantry. | A current report of persistent tinnitus and a lay account of onset; audiometric changes support but are not required. |
| Hearing | Sensorineural hearing loss | Repeated high-intensity impulse noise from the M2 and Mk19 is associated with high-frequency hearing loss. | Audiometry meeting 38 CFR § 3.385 thresholds, entrance/separation comparisons, and a nexus opinion. |
| Shoulder | Rotator cuff pathology and shoulder degenerative changes | Carrying and manipulating the machine gun and tripod loads the shoulders repeatedly during emplacement and movement. | Current imaging or exam findings, in-service treatment or fitness-report references, and a nexus opinion addressing cumulative loading. |
| Lumbar spine | Lumbar strain and degenerative disc disease | Heavy team-weapon loads carried over distance place cumulative axial stress on the lumbar spine. | Current imaging, in-service documentation of field duty, and an opinion addressing cumulative loading. |
| Wrist | Wrist strain and early degenerative changes | Repetitive traverse-and-elevation adjustments and weapon handling load the wrists. | Current diagnosis, in-service complaints if documented, and a nexus opinion addressing repetitive use. |
| Knees | Patellofemoral pain and degenerative arthritis | Movement under heavy team loads and repeated kneeling firing positions stress the knees. | Current diagnosis with range-of-motion findings and documentation of in-service onset. |
| Mental health | PTSD and depressive disorders | Machine gunners attached to maneuver units during deployment faced combat-contact risk comparable to riflemen in the same unit. | A DSM-5 diagnosis, a described stressor, and treatment records showing functional impairment. |
| Neurologic / TBI | TBI residuals and headaches | Blast exposure during combat deployment is possible for gun teams attached to maneuvering elements. | Documentation of the event, reported symptoms, and current neurological findings under the DC 8045 facets. |
Your occupational claim profile
Tick what actually applied to your service. Nothing is stored or sent — this builds a records list you can copy and take to your provider or representative.
Records that corroborate an occupational history
- DD-214 (Member 4 copy) — Primary specialty, awards, badges, and deployment remarks.
- Complete service treatment records — Sick-call entries, profiles, and separation examination.
- Personnel file (OMPF / enlisted record brief) — Every assignment, duty code, and date you served in it.
- Hearing-conservation audiograms (DD 2215 / DD 2216) — Baseline and periodic tests document noise-hazardous duty and threshold shifts.
- Current medical records with a diagnosis — A current disability is required regardless of what the service record shows.
- A medical opinion connecting the condition to service — Occupational history supports the opinion; it does not replace it.
- Lay and buddy statements — Fill gaps where nothing was written down at the time.
- Crew-served weapons course completion records — Documents formal training and range exposure to M240/M2/Mk19.
- Weapons company assignment orders — Corroborates gun-team duty distinct from a standard rifle squad.
- Fitness reports (FitReps) — Narrative record of field duty and deployment history.
An occupational history supports the in-service event or exposure element of a claim. It is not presumptive evidence, it does not diagnose anything, and it does not establish service connection on its own.
Why these claims get denied
Denial language tells you which element of the claim failed. These are the patterns that recur in decisions on 0331 claims.
Noise exposure conceded, hearing claim denied on nexus
VA often accepts crew-served weapons noise exposure, then denies based on an audiologist's opinion citing a normal separation audiogram, which alone does not defeat a hearing claim.
Shoulder or wrist claims denied for lack of in-service documentation
Machine gunners often continued to work through shoulder or wrist pain without a service treatment record entry; without lay evidence of onset and continuity, examiners sometimes discount the claim.
No current diagnosis of the claimed joint
Chronic pain complaints without a diagnosed disability or functional-impairment evidence under Saunders v. Wilkie are commonly denied at the threshold.
Examiner discounts lay statements based on a quiet service record
An opinion that relies mainly on absence of documented treatment, without addressing a Marine's competent account of onset, may be inadequate under Barr v. Nicholson.
Rating understates severity due to a single range-of-motion snapshot
A grant may still understate severity if the exam does not account for flare-ups or repetitive-use loss under 38 CFR §§ 4.40, 4.45 and Correia v. McDonald.
Deployment documented, but claimed condition not linked to specific exposure
A combat deployment may be well documented while the claimed condition is neither presumptive nor supported by a medical opinion tying it to that exposure.
VA accepted my exposure but still denied me
This is the most common outcome for occupational claims: VA concedes what the job involved, then denies on the medical link, the current-diagnosis element, or the rating criteria. A decision review looks at which element the decision actually turned on and what evidence would address it. Oakridge Claims focuses primarily on post-decision representation — Higher-Level Reviews, Supplemental Claims, and Board appeals — and also accepts initial claims and claims for increase based on case fit and current availability, at no fee for initial-claim representation.*
*No fee is charged for representation before VA issues an initial decision. If representation continues after an initial decision, fees may apply to eligible post-decision representation under a written VA-compliant fee agreement. See Fees for details.
0331 claim questions
Does the 0331 MOS automatically prove I have hearing loss?
No. It supports the in-service noise-exposure element. A current disability meeting 38 CFR § 3.385 thresholds and a nexus opinion are still required.
Is machine-gun noise treated differently than rifle noise by VA?
VA does not maintain a separate presumptive category by weapon type, but crew-served weapons are widely recognized as high-intensity noise sources, which can support a strong exposure argument alongside your audiograms.
My shoulder never got treated in the fleet — can I still claim it?
Possibly. Your account of onset, fitness reports describing gun-team duty, and buddy statements from fellow gun-team Marines can help establish continuity even without a service treatment record entry.
Does carrying the tripod and ammunition prove I injured my back?
No. It documents a demanding duty consistent with back strain, but a current diagnosis and a medical opinion connecting it to service are still needed.
I was in a weapons company but also stood rifleman duty — does that matter?
Yes. Your full assignment history, shown in your Basic Training Record and MCTFS entries, can support exposure arguments from any role you held, not only the primary MOS.
Can Reserve machine-gun training support a claim?
It can, depending on duty status. Injuries during active duty for training are generally treated more favorably than those during inactive duty for training.
What records best document machine-gun service specifically?
Crew-served weapons course completion records, weapons-company assignment orders, fitness reports describing gun-team duty, and hearing-conservation audiograms.
Related occupations
Sources
VA accepted my exposure but still denied me
This is the most common outcome for occupational claims: VA concedes what the job involved, then denies on the medical link, the current-diagnosis element, or the rating criteria. A decision review looks at which element the decision actually turned on and what evidence would address it. Oakridge Claims focuses primarily on post-decision representation — Higher-Level Reviews, Supplemental Claims, and Board appeals — and also accepts initial claims and claims for increase based on case fit and current availability, at no fee for initial-claim representation.*
*No fee is charged for representation before VA issues an initial decision. If representation continues after an initial decision, fees may apply to eligible post-decision representation under a written VA-compliant fee agreement. See Fees for details.