01 / Occupational profile
Your 0331 occupational profile
Sustained high-intensity impulse noise
Common occupational factor
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.
Heavy load carriage
Common occupational factor
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.
Repetitive setup, breakdown, and firing-position strain
Common occupational factor
Frequent tripod emplacement, traversing and elevation adjustments, and prone/kneeling firing positions place repetitive strain on the shoulders, wrists, and lower back.
Blast and combat-trauma exposure
Assignment-dependent
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.
Deployment-dependent exposures
Location-dependent
Burn-pit and other airborne-hazard exposure depends on the specific installation and dates of deployment, not on the machine-gun MOS.
02 / Your service
What did you actually do?
Your MOS is the starting point. Your actual assignment, era, equipment, location, and duties determine which parts of the occupational history are relevant. Use the Evidence Builder below to select your actual duties and see records that may corroborate them.
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.
Duties that may vary by assignment
- 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
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Military Occupational Evidence Builder
Based on what you actually did in the military, what records might document it? Select only what applied to you. No name, file number, contact details, free text, or upload. Nothing is saved or sent.
Military service
Marine Corps · 0331 Machine Gunner
For another specialty, open its guide from the MOS library. A job code alone does not establish individual duties or exposure.
Era(s) of service
Deployments
Already have a VA decision?
Your Evidence Builder identifies records that may document your service history. If VA has already decided your claim, the next question is different: what did VA accept, what did VA reject, and why?
Request a free decision review03 / Corroboration
Building your occupational history
Records matter because they can connect a job title to an individual's actual work and circumstances.
Sustained high-intensity impulse noise
Records that may 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
Limit: 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
Records that may 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
Limit: 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
Records that may 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
Limit: 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
Records that may 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
Limit: A combat award does not diagnose a traumatic brain injury; residual disability still requires current clinical findings tied to the event.
Deployment-dependent exposures
Records that may 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
Limit: The MOS alone does not establish where a Marine served; presumptive status depends on documented location and dates.
04 / Evidence standard
What your MOS can — and cannot — establish
May help document
Work performed, circumstances of service, consistency of an alleged exposure, and the nature or duration of duties where supported by individual records.
Does not automatically establish
A diagnosis, medical causation, severity, percentage, presumption, or entitlement to service connection.
05 / Medical evidence
Conditions that may be relevant to the occupational history
This is not a list of conditions to claim. A veteran's actual diagnosis and individual service record determine relevance; occupational evidence is not medical causation.
Hearing +
Tinnitus
Why the occupation may matter: Sustained crew-served weapons fire at close proximity is one of the more intense noise sources in the infantry.
Records and clinical evidence: A current report of persistent tinnitus and a lay account of onset; audiometric changes support but are not required.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Sensorineural hearing loss
Why the occupation may matter: Repeated high-intensity impulse noise from the M2 and Mk19 is associated with high-frequency hearing loss.
Records and clinical evidence: Audiometry meeting 38 CFR § 3.385 thresholds, entrance/separation comparisons, and a nexus opinion.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Shoulder +
Rotator cuff pathology and shoulder degenerative changes
Why the occupation may matter: Carrying and manipulating the machine gun and tripod loads the shoulders repeatedly during emplacement and movement.
Records and clinical evidence: Current imaging or exam findings, in-service treatment or fitness-report references, and a nexus opinion addressing cumulative loading.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Lumbar spine +
Lumbar strain and degenerative disc disease
Why the occupation may matter: Heavy team-weapon loads carried over distance place cumulative axial stress on the lumbar spine.
Records and clinical evidence: Current imaging, in-service documentation of field duty, and an opinion addressing cumulative loading.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Wrist +
Wrist strain and early degenerative changes
Why the occupation may matter: Repetitive traverse-and-elevation adjustments and weapon handling load the wrists.
Records and clinical evidence: Current diagnosis, in-service complaints if documented, and a nexus opinion addressing repetitive use.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Knees +
Patellofemoral pain and degenerative arthritis
Why the occupation may matter: Movement under heavy team loads and repeated kneeling firing positions stress the knees.
Records and clinical evidence: Current diagnosis with range-of-motion findings and documentation of in-service onset.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Mental health +
PTSD and depressive disorders
Why the occupation may matter: Machine gunners attached to maneuver units during deployment faced combat-contact risk comparable to riflemen in the same unit.
Records and clinical evidence: A DSM-5 diagnosis, a described stressor, and treatment records showing functional impairment.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Neurologic / TBI +
TBI residuals and headaches
Why the occupation may matter: Blast exposure during combat deployment is possible for gun teams attached to maneuvering elements.
Records and clinical evidence: Documentation of the event, reported symptoms, and current neurological findings under the DC 8045 facets.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
06 / Exposure record
ILER and toxic exposure
For applicable exposure-related claims, VA may review the Individual Longitudinal Exposure Record (ILER) and a toxic exposure risk activity (TERA) memorandum along with deployment and occupational records. An ILER entry does not automatically establish exposure or service connection.
07 / After a decision
Why a 0331 claim may still be denied
An exposure finding is not the same as a grant. These are examples from the researched guide, not predictions about a particular case.
VA may accept
A duty or event consistent with the service record
But may deny
A diagnosis, medical relationship, or rating element
Record to examine
Decision findings, service and private treatment records, examination rationale, and medical opinions.
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.
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0331 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.
Sources and legal references
General education only; not legal or medical advice. Oakridge Claims is a private business, not affiliated with or endorsed by VA. Nothing here establishes a representative-client relationship or guarantees a result. Free accredited VSO help is available.