Skip to main content
HonestMOS
●InvestigationsCongress made VA disability claims free to file. An entire industry charges veterans anyway — and nobody can stop them.→
←Back to 0331 Machine Gunner — overview, pay, training, civilian translation, reviews
0331E7

Machine Gunner

E-7 (Sergeant First Class) · Marines

E1–E3E-4E-5E-6E-7E8–E9
HEADS UP

Gunnery Sergeant 0331 is the company-level senior NCO tier on the heavy-weapons side — doctrinally weapons company gunnery sergeant (the senior NCO in the battalion's heavy weapons company), company gunny of a rifle company (the company's senior NCO outside the 1stSgt chair), operations chief at battalion S-3 supporting heavy-weapons employment planning, or instructor / cadre billet at SOI / TECOM. The MSgt / 1stSgt (E-8) selection board is the next gate. The SgtMaj's read on you is now the direct driver of the next assignment slate. Career Course done; Advanced Course at SNCO Academy is the next PME horizon.

The Honest MOS Read
Gunnery Sergeant on the 0331 side is the company-level senior NCO tier on the heavy-weapons community, and the Marine Corps's institutional weight on the GySgt rank carries directly into the heavy-weapons community. Doctrinal billets at GySgt for 0331: weapons company gunnery sergeant — the senior NCO in the battalion's weapons company (the company that consolidates the battalion's heavy machine gun, anti-armor, and assault sections; the weapons company gunny owns the heavy-weapons combat power of the entire battalion and reports SNCO-channel to the weapons company 1stSgt and the weapons company commander). Company gunnery sergeant of a rifle company — the company's senior NCO outside the 1stSgt chair, running training, operations, gear accountability, and the company's daily operational rhythm, with deep heavy-weapons technical depth from the 0331 career arc. Operations chief at the battalion S-3 — supporting the battalion operations officer (BN S-3) on heavy-weapons employment planning, training schedule coordination, FTX / CTC integration, and operational planning. Instructor / cadre billet at SOI East / West or TECOM (Training and Education Command) heavy-weapons curriculum development — visible career-shaping billets that compound for the MSgt board. The promotion math at GySgt → MSgt / 1stSgt (E-8) runs through the Marine Corps's centralized selection board under MCO P1400.32D — paper-record review of the full career package (FITREPs, awards, education, PME completion, MCMAP belt, composite history, conduct/proficiency marks, deployment record, the full career package). The 1stSgt vs MSgt fork at E-8 is consequential and explicit: 1stSgt is an MOS designation (the 8999 1stSgt MOS — the company senior enlisted leader job) requiring the 1stSgt school at Camp Lejeune or Camp Pendleton (verify current location/duration against MARADMIN). MSgt is the staff senior NCO track — operations chief at higher headquarters, the various staff senior-NCO billets. Both are SgtMaj-track-aware: which one you're slated into is shaped by the SgtMaj's read of your career arc. The Advanced Course (Advanced School / Career School Advanced) at the SNCO Academy is the structured PME at the GySgt tier — required for promotion in most cases (verify current PME requirements against MCO and MARADMIN). Delivered at the regional SNCO academies for resident or via CDET for non-resident. The course covers senior-NCO leadership, organizational dynamics, the Marine Corps's senior-enlisted role in policy and force planning, and the strategic context that GySgts and 1stSgts/MSgts operate within. The SgtMaj's read becomes the direct driver at GySgt. The Marine Corps's small-community dynamic at the SNCO level is structurally tight — the SgtMaj at the BN level talks to the SgtMaj at the regimental and division level; the GySgts visibly tracked for 1stSgt are visibly tracked by name across the SgtMaj community. The 0331 heavy-weapons community is even tighter than the 0311 rifleman community at this rank tier — the heavy-weapons senior NCOs at 1st / 2nd / 3rd Marine Division weapons companies and the various MEU heavy weapons sections know each other and trade information about which GySgts are showing the 1stSgt potential. Visible career-shaping moves at GySgt — a clean B-billet tour (DI / MSG / recruiter / instructor if not already complete), a strong FITREP cycle as weapons company gunny on a MEU deployment, a high-visibility instructor billet at SOI / TECOM, or a senior MARSOC billet — all compound on the centralized E-8 board's read. The weapons company gunny billet at GySgt is the load-bearing heavy-weapons leadership tier in the Marine infantry battalion. You own the battalion's heavy machine gun section (multiple M240 / M2 / MK19 crews), the anti-armor section (Javelin / Mk153 SMAW / the various anti-armor systems per the battalion's TO&E and current Marine Corps Force Design organizational structure — verify the current TO&E against the current MCO and MARADMIN updates), and the integration of the heavy-weapons combat power into the battalion's maneuver operations. The weapons company gunny is the senior heavy-weapons technical authority in the battalion and the SgtMaj's primary tier-1 heavy-weapons read. The MARSOC / MEU / III MEF assignment slate at GySgt continues. MARSOC GySgts as senior Marine Raider Operators or instructor billets at MARSOC Schools (verify current MARSOC SNCO career model and CSO progression timeline against MARADMIN). MEU heavy-weapons operations chief on a deployment cycle. III MEF rotation to Okinawa as the weapons company gunny or operations chief in a forward-deployed billet. SOI East/West instructor cadre on the heavy-weapons curriculum. MSG senior leadership at the embassy program. The retirement math at GySgt with 14-18 years TIS is now the load-bearing financial decision. The 20-year retirement math (BRS multiplier 2.0% per year of service, TSP match accumulating, continuation pay at 12 years already collected or in window) compounds. The math of staying for 1stSgt / MSgt (E-8), GySgt-of-Marines / SgtMaj progression (E-9), and the senior-Marine retirement vs ETSing with 14-18 years as a senior 0331 GySgt into a defense-industry / federal civil service / federal LE career is the conversation. The post-service market for 0331 GySgts is structurally strong. Defense contracting (Triple Canopy, Constellis, Tier 1, and the long tail of security services firms) values senior Marine heavy-weapons NCO experience visibly; federal LE (Border Patrol senior leadership tracks, FBI tactical, US Marshals tactical, ATF) values the SNCO leadership package; federal civil service (DoD civilian roles, OPM-classified GS-12 / GS-13 program management slots) hires Marine GySgts into program management. The combination of GySgt leadership + 0331 heavy-weapons combat experience + clearance + deployment record is materially valuable for the firearms-instruction, training, and operations-leadership markets specifically.
Career Arc
  • 01SSgt → GySgt pin-on via centralized SNCO selection board under MCO P1400.32D.
  • 02Weapons company gunny / rifle company gunny / S-3 operations chief / SOI instructor assumption — doctrinal GySgt billet.
  • 03Advanced Course PME at SNCO Academy — resident or CDET non-resident.
  • 04MEU PTP / MEU deployment as weapons company gunny or operations chief.
  • 05SgtMaj-track visibility: clean FITREP cycle, B-billet completion record, high-visibility staff / instructor / MARSOC billet.
  • 061stSgt vs MSgt fork — explicit at the E-8 board, slate-driven by SgtMaj read.
  • 07Centralized SNCO board for MSgt (E-8) / 1stSgt — paper-record selection.
Common Screwups
  • ×Underestimating the SgtMaj-community dynamic in the heavy-weapons community. The 0331 senior NCO community is small and visible — your read at GySgt propagates by name across BNs and regiments.
  • ×Missing Advanced Course PME. The E-8 board reads PME explicitly; missed gates are visible and there's no recovery within a board cycle.
  • ×Phoning weapons company gunny role. The weapons company gunny owns the battalion's heavy-weapons combat power; SgtMaj and BN SgtMaj read it through the 1stSgt and CO directly.
  • ×NJP / DUI / fraternization / inappropriate relationship findings — terminal for E-8 board competitiveness and any SgtMaj-track slate.
  • ×Letting the post-service market decision drift past the optimal window. Senior 0331 GySgts with clearance and clean records are valuable now in the firearms-instruction and training markets specifically; the calculus of staying for E-8 vs ETSing is the most important financial decision of mid-career.

A Day in the Life

  • 0500Wake. PT gear on. Phone check — overnight company / battalion emergencies. Marine in jail in town? Family deathgram? CO emergency? BN SgtMaj call? You are the senior heavy-weapons NCO the company looks to first. The 1stSgt hears about it as you walk into the company office.
  • 0530PT formation. You report company gunny accountability to the CO and the 1stSgt; the 1stSgt rolls it up to the BN SgtMaj. The regimental SgtMaj walks the formation occasionally; he reads the company by reading the company gunny and the 1stSgt.
  • 0545-0700Unit PT. You run the company's plan with the CO and the 1stSgt. You walk the company, check on Marines from the last sensing session, adjust the SSgt platoon sergeants as the day evolves. The GySgt who does PT with the company is the GySgt the formation believes when the standard gets enforced.
  • 0700-0900Hygiene, chow, change to utilities. You spend 20 minutes with the CO and the 1stSgt — the day's training, the BN BUB items rolling down, the BN SgtMaj's tasking, the regimental SgtMaj's items if any.
  • 0900First formation. The CO addresses the company; you and the 1stSgt stand behind him. The SSgt platoon sergeants translate the company's tasks to their platoons. You verify execution during the morning walk-around through the armory, the supply room, and the company work spaces.
  • 0915-1130Battalion-level work. You are at the BN BUB with the CO and the 1stSgt. You walk the company's gear status (the full heavy-weapons fleet serviceability), the company's training cards and PCC/PCI status for the next BN-level event, the company's FitRep cycle status. You may be at the BN S-3 for an operational planning huddle on the next MCCRE / ITX milestone or at the BN SgtMaj's company gunny huddle.
  • 1130-1300Chow. You eat with the BN command team or the company gunnies. Conversation is battalion-level and regimental-level: training, slates, the E-8 board cycle, the 1stSgt vs MSgt fork conversation, the company-level MCCRE / ITX status, the MEU PTP or III MEF UDP rhythm.
  • 1300-1500Afternoon work. FitRep drafting (you write the SSgt FitReps as reporting senior; the 1stSgt reviews; the CO signs). Company training schedule input for the next quarter. Mentorship sessions with the SSgt platoon sergeants on bench planning. The 1stSgt may pull you to act as 1stSgt for the afternoon while he goes to the BN SgtMaj's 1stSgt council.
  • 1500-1630Final formation. The CO briefs; you and the 1stSgt brief company-level adjustments; the SSgt platoon sergeants brief their platoons. Sensitive items, end-of-day accountability. The CO and you walk the armory and the company work spaces on critical end items.
  • 1630-1800Company release. You stay 60-90 minutes with the CO and the 1stSgt — AAR on the day, prep for tomorrow, the CO's questions on the next E-8 board cycle or the next FitRep cycle, the company's upcoming live-fire risk assessment chain.
  • 1800-2000Personal time. Married GySgts: family. Single GySgts: gym, study (Advanced Course CDET modules if non-resident), E-8 board package build if 18-24 months out. If you are in the post-GySgt billet window, you are reading the current MARADMINs on the senior-NCO assignment slate, the MARSOC SNCO career model if applicable, and the post-service market landscape (SkillBridge, VA disability claim pre-EAS, defense industry / federal LE positioning).
  • 2000-2200After-hours coordination with the CO, the 1stSgt, the SSgts, or a Marine in crisis. The GySgt's phone is on. Family-emergency calls, after-duty NJP notifications, casualty assistance preparation, the SSgt who needs to talk through a Sgt's page-11 or a platoon climate issue.
  • 2200Lights out.
  • MEU / ITX / UDP / Bridgeport rotationThe clock collapses. You are the senior enlisted face of the company (weapons company or rifle company) during a Twentynine Palms ITX, a MEU SOC certification, a III MEF UDP rotation, or a MWTC Bridgeport cold-weather rotation. The MCCRE evaluator is writing the company's grade. The 1stSgt reads it. The BN SgtMaj reads it. The regimental SgtMaj reads it. The next E-8 board reads it.

Weekly Cadence

The Mon-Fri rhythm at GySgt level is the company gunny version of the 1stSgt rhythm. Monday is the heaviest planning day — you read the BN SgtMaj's Friday release, adjust the company's plan to match the battalion's tasking, brief the CO and the 1stSgt by mid-morning, brief the SSgt platoon sergeants by the company morning huddle. Tuesday-Wednesday are training execution; you observe, the SSgt platoon sergeants run platoons, the section leaders run sections and gun teams. Thursday is maintenance, armory, motor pool, or company-level event prep; Friday is the BN-level event and release. The week's second rhythm is the BN-level work: the company gunny huddle with the BN SgtMaj (weekly), the FitRep cycle drafting and review (semi-annual at the company-gunny level), the company training schedule input (monthly), the company climate-survey response cycle (semi-annual), and the BN command climate cycle. The GySgt who is on the 1stSgt bench is at the BN SgtMaj's office at least weekly; the GySgt who is not is missing the BN-level briefing he needs to compete at the next E-8 board. The MSgt-track senior NCO is similarly at the BN-level / regimental-level staff senior NCO conversations — the BN S-3 senior NCO huddle, the regimental S-3 operational planning meetings. The week's third rhythm is the company's combat-effectiveness and climate work — MCCRE preparation and execution cycles, ITX / MEU PTP milestones, the heavy-weapons platform technical depth maintenance (you run quarterly platform refresher sessions for the SSgts and the company corpsman as appropriate), the family readiness coordination with the unit FRO, and the SAPR / EO / climate-survey response actions when needed. The GySgt who treats the combat-effectiveness work as the SSgts' problem is the GySgt whose company's gear status fails the next BN CO walkthrough; the GySgt who walks the armory every Monday morning at 0700 with his SSgt platoon sergeants is the GySgt whose company does not surprise the BN SgtMaj on a Friday afternoon inspection. When the company is in MEU PTP workup the cadence shifts toward MEU-SOC certification milestones, integrated live-fires across the BLT, and the various MEU mission profile training (TRAP, NEO, embassy reinforcement, MARSOC support, contingency response). When the company is in the deployed phase of the MEU afloat or the III MEF UDP cycle, the GySgt is the senior heavy-weapons NCO inside the company on the ship or at the III MEF Camp Hansen / Camp Schwab posture. The daily rhythm collapses to operational tempo and the on-call MEU contingency mission profile cycle.

Key Skills — How to Drill Each

  1. 01
    Run a weapons company gunny billet — own the battalion's heavy-weapons combat power, integrate with the rifle companies, defend the company training and tasking calendar at battalion BUB without surprises.
    The weapons company gunny is the senior NCO in the battalion's weapons company. You own the heavy machine gun section (multiple M240 / M2 / Mk19 crews on JLTV / MRZR mounts), the anti-armor section (Javelin / Mk153 SMAW / the various anti-armor systems per the battalion's current TO&E under Marine Corps Force Design — verify against current MCO and MARADMIN updates), and the integration of heavy-weapons combat power into the battalion's maneuver operations. The company gunny billet is the GySgt billet that the BN SgtMaj reads as the load-bearing heavy-weapons leadership tier; the weapons company commander defends his FitRep narratives on your performance. Build the company training and tasking calendar 120-150 days out — T&R events from NAVMC 3500.44 at the company level, MCCRE / ITX milestones tied to the BN PTP, BN-level live-fire integration with the rifle companies. Brief the CO, brief the BN S-3, lock it at the BN training board. The GySgt whose calendar survives the next quarter without major revision is the GySgt the BN SgtMaj defends at the E-8 board.
  2. 02
    Mentor three to four SSgts as the next GySgt cohort — Career Course completion, B-billet record, FitRep RV profile, MCMAP belt progression, and the early 1stSgt vs MSgt fork conversation.
    Each SSgt platoon sergeant gets quarterly mentorship sessions with development objectives tied to the SSgt → GySgt centralized board package. Career Course completion (resident at SNCO Academy or CDET non-resident), B-billet completion or slot identification, FitRep RV pattern across the most recent three reports, MCMAP Black Belt / BBI / BBIT progression, composite history visibility. The 1stSgt vs MSgt fork conversation opens at SSgt-late / GySgt-early; the GySgt who reads each SSgt's career arc honestly (troop-leadership-track or staff-SME-track) is the GySgt the SSgts and the company gunny community trust. The GySgt who graduates two SSgts to GySgt-promotable in 36 months is the GySgt the BN SgtMaj names for the 1stSgt bench; the GySgt who lets his SSgts drift on the school slot or B-billet window is the GySgt whose own E-8 board reads thin on documented mentorship.
  3. 03
    Run a company through an ITX rotation at Twentynine Palms (MCAGCC), a MWTC Bridgeport cold-weather rotation, a III MEF UDP, or a MEU deployment as the company gunny — daily operational rhythm, gear status, casualty rehearsals, OPSEC discipline.
    The ITX rotation at Twentynine Palms (MCAGCC) is the pre-deployment integrated training the company runs through; MWTC Bridgeport is the Marine Corps Mountain Warfare Training Center for cold-weather / mountain operations; III MEF UDP is the 6-month forward-deployed rotation at Okinawa (Camp Hansen / Camp Schwab); the MEU is the deployed phase afloat. The GySgt company gunny is on every range, every back-brief, every AAR, every operational planning huddle with the CO and the BN S-3. The company gunny who runs the company through a clean ITX / Bridgeport / UDP / MEU without surprising the BN SgtMaj is the GySgt the regimental SgtMaj names for the 1stSgt slate; the company gunny who creates surprises is the GySgt the BN SgtMaj reads cold at the next E-8 board.
  4. 04
    Defend the company's combat readiness honestly at the BN BUB and the BN command climate cycle — MCCRE rating, retention metrics, SAPR / EO climate index, FitRep RV pattern, family readiness status.
    The BN CO and BN SgtMaj rely on the company gunnies (and the 1stSgts) for company-level ground truth. MCCRE rating from the most recent evaluation cycle, retention metrics pulled from the unit career planner, SAPR / EO climate-survey response status, FitRep RV pattern across the company's SSgts and Sgts, family readiness status from the unit FRO — the GySgt who briefs this honestly weekly to the CO and at the BN BUB to the BN command team is the GySgt whose company is the BN SgtMaj's preferred name on the next slate. The GySgt who lets the briefing become a chamber-of-commerce pitch is the GySgt the BN SgtMaj corrects in front of the other company gunnies once and replaces on the slate after.
  5. 05
    Maintain heavy-weapons platform technical depth at the senior NCO level — M240 sustained-fire procedure, M2 .50 cal headspace and timing, Mk19 belt-link feed mechanics, 60mm mortar fire commands, SMAW employment math, integrated WpnsPlt fires planning.
    The 0331 community values platform technical mastery as the visible competence signal at GySgt+. The senior NCOs at the various MEU heavy weapons sections and the weapons company gunnies across MarDiv read each other by platform depth — the GySgt who can quote the current MCRP 3-15-series cold during a company back-brief, who can teach a Mk19 belt-link feed mechanics class to the section without notes, and who can write a 60mm mortar fire commands lesson plan that the 0341 community will sign off on is the GySgt the institutional 0331 community names to the 1stSgt slate. The GySgt who lets platform depth drift after pin-on is the GySgt whose institutional credibility lags and whose 1stSgt board read suffers.
  6. 06
    Run the SgtMaj-track visibility cycle — BN SgtMaj read, regimental SgtMaj read, B-billet completion record visible on the record brief, joint duty conversation if applicable, MARSOC senior NCO conversation if MARSOC-aligned.
    The Marine Corps's small-community dynamic at the SNCO level means the SgtMaj community talks across battalions and regiments about which GySgts are showing the 1stSgt potential. Visible career-shaping moves at GySgt: a clean B-billet tour (DI / MSG / recruiter / instructor if not already complete), a strong FitRep cycle as weapons company gunny on a MEU or UDP, a high-visibility instructor billet at SOI East / West or TECOM, or a senior MARSOC billet — all compound on the centralized E-8 board's read. The GySgt who runs the visibility cycle deliberately — quarterly conversation with the BN SgtMaj on the next billet, semi-annual read with the regimental SgtMaj if invited, the record-brief audit before the next slate window — is the GySgt who selects at the 1stSgt board.

Manuals & References — What Chapters Matter

  • MCO 1400.32 — Marine Corps Promotion Manual.
    Centralized SNCO selection board mechanics for the GySgt → MSgt / 1stSgt (E-8) board are in this MCO. Paper-record review of the full career package — FitReps, awards, education, PME completion, MCMAP belt, composite history, conduct / proficiency marks, deployment record. The 1stSgt vs MSgt fork at E-8 is consequential and explicit; the slate decisions for the various senior billets are governed by this MCO. Re-read at pin-on, before each FitRep cycle, and again before the centralized E-8 board.
  • MCO 1610.7 — Performance Evaluation System.
    You are now reporting senior on the company's SSgt platoon sergeants and reviewing officer on the Sgts. Read the MCO cold; teach the SSgts how to write Section A; defend the FitRep RV profile at the battalion FitRep review board. The senior reporting official's RV credibility at HQMC reads on whether the SSgts you rated as competitive actually got selected at the next GySgt board. Re-read before every cycle and before the centralized E-8 board.
  • Advanced Course (Advanced School / Career School Advanced) at SNCO Academy curriculum.
    The Advanced Course is the structured PME at the GySgt tier — required for promotion in most cases (verify current PME requirements against MCO and MARADMIN). Delivered at the regional SNCO academies for resident or via CDET for non-resident. The course covers senior-NCO leadership, organizational dynamics, the Marine Corps's senior-enlisted role in policy and force planning, and the strategic context that GySgts and 1stSgts / MSgts operate within. Build the packet 12-18 months out from the E-8 board; the SNCO Academy seat at GySgt rank fills early in the FY.
  • NAVMC 3500.44 — Infantry Training and Readiness Manual (company-level collective tasks).
    You build the company-level training plan against the T&R Manual's company-level collective tasks. At GySgt the chapters that matter are the weapons company collective tasks (heavy machine gun integration, anti-armor integration, integrated weapons company employment in support of the rifle companies) and the rifle company collective tasks (the units your guns support). Re-read the current edition annually; the T&R Manual updates via MARADMIN.
  • MCWP 3-01 — Offensive and Defensive Tactics for the Marine Air-Ground Task Force; MCDP 1 — Warfighting; MCDP 1-3 — Tactics.
    At GySgt you teach these to the SSgts and Sgts; you do not consume them. MCWP 3-01 is the operational doctrine the BN CO and BN S-3 plan from; MCDP 1 and MCDP 1-3 are the foundational warfighting doctrine the Commandant's Reading List reinforces. The GySgt who can quote MCWP 3-01 in the context of a current MCCRE / ITX problem is the GySgt the BN CO consults; the GySgt who has not re-read it since Sergeants Course is the GySgt whose institutional credibility lags.
  • The current MARADMIN catalog — GySgt → MSgt / 1stSgt board cycle, SRB tier, B-billet windows, T&R updates, MCCRE / ITX guidance, the 0369 conversion guidance, MARSOC SNCO career model.
    MARADMINs are the Marine Corps's standing operational guidance — they move with policy cycles and operational requirements. The GySgt who reads each new MARADMIN as it drops is the GySgt whose company is ahead of the policy curve; the GySgt who waits for the BN SgtMaj to brief the MARADMIN is the GySgt who is reacting instead of leading. Pull the current MARADMIN catalog weekly; brief the relevant MARADMINs to the company SSgts.

Standards — How to Hit Each

  • Advanced Course (Career School Advanced) graduate at SNCO Academy — required for E-8 promotion in most cases.
    Verify current PME requirements against MCO and MARADMIN. Delivered at the regional SNCO academies for resident or via CDET for non-resident. Build the packet 12-18 months out from the E-8 board. The GySgt who misses Advanced Course is the GySgt whose E-8 board package reads thin on PME; there is no recovery within a board cycle.
  • FitRep RV profile that the senior reporting official can defend at HQMC — the bar for the E-8 board is whether your rated SSgts and Sgts get selected at their respective boards.
    The reporting senior's RV profile under MCO 1610.7 at this rank is judged by HQMC across all rated Marines. If your SSgts and Sgts are not pinning at the rates your FitRep narratives implied, the reporting senior's RV credibility drops, the BN SgtMaj pulls back on your defense, and the centralized E-8 board reads the gap. The way to keep the RV defensible is honest performance — write to the MCO 1610.7 standard, not to inflation. The company gunny whose rated Marines actually get selected at their respective boards is the GySgt whose RV pattern reads competitive at the E-8 board.
  • Company MCCRE / ITX rating in the top tier of the battalion; pre-deployment training delivered on the timeline the CO signed for; UDP / MEU deployment record clean.
    MCCRE / ITX evaluators write the company-level grade; the BN SgtMaj reads it; the regimental SgtMaj reads it; the next E-8 board reads it. Pre-deployment training (PTP) delivered on the timeline the BN CO signed for, with the gear status the company gunny owns at the company-level inspection cycle. UDP at III MEF or MEU afloat completed with no significant negative incident on the record. The GySgt whose company hits the top tier on MCCRE and whose deployment record is clean is the GySgt the BN SgtMaj defends at the E-8 board.
  • 1st-Class PFT and CFT; MCMAP Black Belt Instructor (BBI) minimum, Black Belt Instructor-Trainer (BBIT) preferred at GySgt.
    MCO 6100.13 and MCO 1500.54 standards. The formation watches the GySgt's PFT / CFT scores more than anyone's except the 1stSgt; the 0331 community expects the GySgt to carry weight on a battalion hump under the gun load. BBI is the bar at GySgt; BBIT extends the instructional credential and is what the company gunny notes on the next FitRep. Both credentials are visible on the E-8 board package.
  • Zero senior-NCO-level integrity incidents — NJP / DUI / fraternization / inappropriate relationship findings, financial mismanagement, OPSEC violations. One ends E-8 board competitiveness permanently.
    GySgt integrity is binary at the centralized board level. NJP (Marine Corps NJP under UCMJ), DUI, fraternization findings (relationships across the SNCO / officer line or with subordinates), inappropriate relationship findings, financial mismanagement that the CO has to counsel you about, OPSEC violations that surface in the BN IG report — any one of these is terminal for the E-8 board and any SgtMaj-track lateral move. The BN SgtMaj and BN CO do not protect GySgts through integrity failures.

Technical Mistakes — Concrete Consequences

  • Letting one platoon sergeant or section leader drift because you trust him.
    That is the section the IG inspection lands on and the company gunny absorbs. The SSgt platoon sergeant the GySgt protects out of personal loyalty is the SSgt whose climate problem surfaces at the next BN climate-survey response cycle. The CO learns about it from the BN SgtMaj; the 1stSgt learns about it from the CO; the GySgt company gunny is the named party. The fix is to counsel the SSgt honestly in writing — page-11 entry, formal counseling — or replace him. Protecting him through a documented gap is the GySgt's E-8 board, not the SSgt's.
  • Confusing being tight with the CO with being aligned with the CO.
    The company commander needs the GySgt to push back honestly in his office with the door closed. The GySgt who agrees with the CO publicly and privately on every decision is the GySgt who loses the CO's trust the first time the CO makes a wrong call and the GySgt did not warn him. The CO writes a thin FitRep on the GySgt who failed to give him the read; the BN SgtMaj reads the thin FitRep at the E-8 board. The fix is the office conversation with the door closed; alignment in formation is the output, not the input.
  • Carrying a personal feud with a peer GySgt into the company.
    The BN SgtMaj notices, the FitRep board notices, and the slate writes itself. The GySgt who lets a peer feud into the company gunny conversation, the company-level coordination with the other companies, or the BN-level operational planning is the GySgt the BN SgtMaj reads as a leadership-maturity gap. The 1stSgt and BN SgtMaj both factor the maturity read into the next slate; the regimental SgtMaj reads it too. The fix is the peer-mediation conversation with the other GySgt and the BN SgtMaj if needed; carrying the feud is terminal.
  • Skipping the family readiness piece because 'the spouses run that.'
    You sign the unit health-of-the-force input for a reason. The unit FRO runs the family readiness program at the company level; the GySgt company gunny owns the unit's family readiness rollup to the BN. The BN SgtMaj reads the family readiness status as part of the unit health-of-the-force input. The GySgt who lets family readiness drift is the GySgt whose unit health-of-the-force input reads thin; the BN CO and BN SgtMaj both factor the family readiness read into the next slate. The fix is monthly meetings with the unit FRO and the spouses' leadership; the visible engagement is the input the BN SgtMaj reads.
  • Going around the 1stSgt to the BN SgtMaj.
    You will be wrong on the facts and relieved on the spot — and the Corps does not forget that promotion. The chain runs through the 1stSgt for a reason; the BN SgtMaj will not field a company gunny who bypasses the 1stSgt unless the 1stSgt is the named party in the IG complaint. The GySgt who goes around the 1stSgt on routine business is the GySgt who loses the 1stSgt's defense at the E-8 board and the BN SgtMaj's defense at the same board. The fix is the 1stSgt conversation; the BN SgtMaj is the 1stSgt's escalation path, not the GySgt's.

Career Decisions at This Rank

  • 1stSgt vs MSgt fork at E-8 — troop-leadership pinnacle vs staff senior NCO track.
    The 1stSgt vs MSgt fork at E-8 is the most consequential GySgt-to-E-8 career decision. 1stSgt is the troop-leadership senior NCO (the 8999 1stSgt MOS, requiring the 1stSgt school — verify current school location and duration against MARADMIN): company senior enlisted leader, daily formation, discipline, counseling, climate, family readiness, casualty assistance. MSgt is the staff senior NCO track: operations chief at battalion S-3, regimental S-3, division or MEF; intel chief at S-2; senior MOS-functional billets at TECOM, HQMC manpower (MMPB), SOI / MCRD / TBS senior cadre. Both pin at E-8; the BN SgtMaj's read of your career arc and your visible billet history shape which slate you are on. Honest self-assessment 18-24 months before the E-8 board with the BN SgtMaj is the load-bearing conversation. The line-troop-leadership GySgt who has run a clean company gunny tour, a clean B-billet, and a clean MEU deployment is the GySgt the slate names to the 1stSgt track; the staff-SME GySgt with deeper staff-section history (S-3 ops chief, S-2 intel, S-4 logistics senior NCO, or institutional senior cadre at SOI / TECOM) is the GySgt the slate names to the MSgt track.
  • 0369 (Infantry Unit Leader) conversion at GySgt+.
    0369 is the senior infantry NCO MOS — historically the conversion MOS for senior 0311 and 0331 (and other 03XX) NCOs at GySgt+ when the senior infantry leadership pool consolidates. The 0369 GySgt and above competes for the broader senior infantry leadership billets (rifle company gunny at GySgt, rifle company 1stSgt at E-8, the broader infantry SgtMaj slate at E-9). The decision: stay 0331 through E-8 (weapons company gunny at GySgt, weapons company 1stSgt at E-8 on the troop-leadership track, MGySgt master gunner billets at division / MARSOC on the occupational SME track) or convert to 0369 and compete in the broader senior infantry pool. The conversation opens with the monitor and the BN SgtMaj at GySgt; the binding conversion typically happens between GySgt and the E-8 board. Verify the current 0369 conversion guidance against the current MARADMIN.
  • Post-GySgt billet — weapons company gunny, rifle company gunny, S-3 ops chief, SOI / TECOM instructor, MARSOC senior NCO, MEU heavy-weapons operations chief.
    The post-GySgt billet shapes the E-8 board package directly. Weapons company gunny is the doctrinal GySgt billet on the heavy-weapons side; rifle company gunny (post-0369 conversion or 0311 lateral) puts you in the broader infantry leadership pool; S-3 ops chief at battalion or regimental level is the staff-track billet that signals MSgt-track at E-8; SOI East / West instructor cadre or TECOM heavy-weapons curriculum development is the institutional senior NCO billet that compounds on the MSgt board read; MARSOC senior NCO (MARSOC GySgts as senior Marine Raider Operators or instructor billets at MARSOC Schools — verify current MARSOC SNCO career model against MARADMIN) is its own ecosystem with different post-service market dynamics; MEU heavy-weapons operations chief on a deployment cycle puts the deployment-record stamp on the package. Honest conversation with the monitor and the BN SgtMaj 12-18 months out is the load-bearing input.
  • Re-enlistment / SRB at the 14-18 year window — the late-career financial decision.
    The GySgt at 14-18 years TIS is in the late-career reenlistment window. The 20-year retirement math under BRS (2.0% per year of service multiplier — 40% at 20, capped per the current retirement system; TSP match accumulating; continuation pay at 12 years already collected or in window) compounds. The math: stay for E-8 (1stSgt / MSgt) and 18-22 years TIS to ride the pension up, then potentially compete for E-9 (SgtMaj / MGySgt) at 24+ years TIS — or EAS at 14-18 years and convert to defense industry / federal LE / federal civil service mid-career. The senior 0331 GySgt market with clearance and clean record is structurally strong now (firearms instruction, training, security contracting at the senior level, federal LE entry at the senior level); the 20-year retirement math is materially better than 14-16 years out. Run the math with a financial counselor; the variables are real either way.
  • Post-service market planning — defense contracting, federal LE, federal civil service, firearms-instruction / training markets, MARSOC-adjacent civilian career.
    Senior 0331 GySgts with clearance, Advanced Course credentials, and a clean weapons company gunny FitRep profile are valuable to defense industry on day one out the gate. Companies hiring at this profile: Triple Canopy, Constellis, Tier 1, and the long tail of security services firms — the firearms-instruction, training, and operations-leadership markets specifically value the senior heavy-weapons NCO leadership package. Federal LE at the senior level: Border Patrol senior leadership tracks, FBI tactical, US Marshals tactical, ATF. Federal civil service (DoD civilian roles, OPM-classified GS-12 / GS-13 program management slots) hires GySgts into program management. The senior NCOs who landed the best post-service careers planned 24-36 months ahead — SkillBridge slot identification (DoD-wide transition program, up to 180 days of last-permanent-duty civilian work experience at industry partners), VA disability claim pre-EAS via the Benefits Delivery at Discharge (BDD) program, clearance currency, defense-industry relationship building, federal LE / federal civil service positioning. The GySgt who waits until terminal-leave-orders date lands in the lower tier of available billets.

How the Seat Varies by Unit Type

  • Weapons company gunny (battalion-level weapons company — the senior NCO of the company that consolidates the battalion's heavy-weapons combat power)
    The weapons company gunny is the doctrinal GySgt billet on the heavy-weapons side. You own the battalion's heavy machine gun section (multiple M240 / M2 / Mk19 crews on JLTV / MRZR mounts), the anti-armor section (Javelin / Mk153 SMAW / the various anti-armor systems per the battalion's current TO&E under Marine Corps Force Design — verify against current MCO and MARADMIN updates), and the integration of heavy-weapons combat power into the battalion's maneuver operations. The weapons company commander defends his FitRep narratives on your performance; the BN SgtMaj reads the weapons company gunny as the load-bearing heavy-weapons leadership tier. This is the most common GySgt 0331 billet; the BN SgtMaj and regimental SgtMaj slate flow through it.
  • Rifle company gunny (post-0369 conversion or 0311 lateral — the company's senior NCO outside the 1stSgt chair, running the daily operational rhythm)
    The rifle company gunny is the GySgt billet inside the rifle companies; many senior 0331 GySgts who convert to 0369 (Infantry Unit Leader) compete for this billet. The rifle company gunny runs the company's daily operational rhythm with the 1stSgt and the CO, owns the training calendar and gear accountability, and brings the heavy-weapons technical depth from the 0331 career arc to the rifle company's weapons platoon. The BN SgtMaj reads the rifle company gunny in the broader infantry leadership pool; the rifle company 1stSgt and the broader infantry SgtMaj slate flow through it.
  • S-3 operations chief at battalion or regimental level (staff-track GySgt billet supporting heavy-weapons employment planning)
    The S-3 operations chief is the staff senior NCO billet at the BN or regimental S-3 — supporting the battalion or regimental operations officer on heavy-weapons employment planning, training schedule coordination, FTX / CTC integration, and operational planning. The OPTEMPO is the staff-section operational planning cycle, distinct from the line-company gunny rhythm. The S-3 ops chief at GySgt who runs a clean staff tour and brings the 0331 heavy-weapons technical depth to the BN-level operational planning is the GySgt the BN SgtMaj reads as MSgt-track at E-8; the senior reporting official's RV profile reads on the staff-section operational planning output.
  • Instructor / cadre billet at SOI East (Camp Geiger / Camp Lejeune area), SOI West (Camp Pendleton), or TECOM (Training and Education Command) heavy-weapons curriculum development
    The SOI / TECOM instructor cadre billet is the institutional senior NCO billet at the Marine Corps schoolhouses or the training command. The OPTEMPO is calmer than line FMF but the institutional-cadre work is materially career-shaping for the MSgt / MGySgt track. The senior heavy-weapons curriculum development billets at TECOM shape the next generation of 0331 / 0369 instruction; the senior MOS roadmap visibility is real. Many senior 0331 MGySgts came through the SOI / TECOM senior cadre at some point.
  • MARSOC senior NCO (Marine Raider Regiment GySgt billets — senior Marine Raider Operator or instructor at MARSOC Schools)
    MARSOC GySgts as senior Marine Raider Operators or instructor billets at MARSOC Schools run at a different OPTEMPO and standard than line FMF. The MARSOC SNCO community is structurally tighter than the line FMF SNCO community; verify the current MARSOC SNCO career model and CSO progression timeline against MARADMIN. The post-service market for senior MARSOC NCOs is materially different — Tier 1 contracting at the higher tiers, federal LE at the federal tactical level, and the SOF-adjacent civilian career arc. The MARSOC senior NCO chain has its own slate dynamics distinct from line FMF and the line 0331 community.

What Good Looks Like at This Rank

The good GySgt 0331 is the SNCO the BN SgtMaj is willing to send to the worst billet in the battalion — weapons company gunny on a MEU PTP workup, master gunner billet at the schoolhouse, instructor cadre at SOI East / West, MARSOC senior NCO progression if MARSOC-aligned — because the unit comes back better and the FitReps come back clean. His three to four SSgts get GySgt at the next centralized board; his company's MCCRE rating sits in the top tier of the battalion; the FPF plan in the company defense is the one the BN CO briefs at regiment; his deployment record (MEU / UDP / named operation) is clean; his FitRep RV profile across the most recent three reports sits above the battalion's GySgt average. His relationship with the company commander is the GySgt-and-CO relationship the Corps designed — he pushes back honestly in the CO's office with the door closed; he walks out aligned in formation. The 1stSgt trusts him with the worst news at 0200; the BN SgtMaj names him to the BN-level SNCO huddle as the company gunny's preferred voice; the regimental SgtMaj has already mentioned his name to the BN SgtMaj for the next 1stSgt or MSgt slate. His platform technical depth on the M240 / M2 / Mk19 / 60mm mortar / SMAW is visible — the GySgt who can teach the section a Mk19 belt-link feed mechanics class without notes is the GySgt the 0331 institutional community names to the 1stSgt slate. The grooming GySgt at this rank is the one whose BN SgtMaj has already started the 1stSgt vs MSgt fork conversation, whose company's MCCRE rating is the BN's preferred name on the slate, whose three SSgts are on the BN SgtMaj's tracked GySgt-bench, who has Advanced Course done and the post-GySgt billet history visible on the record brief (MEU as company gunny, UDP at III MEF, instructor billet at SOI or TECOM, MARSOC senior NCO if applicable), and whose 1st-Class PFT / CFT and Black Belt Instructor-Trainer MCMAP credentials are the floor not the ceiling. The 0369 conversion conversation has opened with the monitor; the senior infantry leadership pool is the conversation. The centralized E-8 board reads paper; the GySgt who built the paper through 36 months of disciplined company gunny work is the GySgt who pins MSgt or 1stSgt at the next slate.

Preview — The Next Rank

MSgt / 1stSgt at E-8 is the next gate. 1stSgt (the 8999 1stSgt MOS — the company senior enlisted leader job, requiring the 1stSgt school) is the troop-leadership senior NCO billet: you run 130-180 Marines, the company office, the platoon sergeants and company gunny, the training calendar, the discipline rhythm, the family readiness program, and the boundary between what the CO needs and what the company can deliver. MSgt is the staff senior NCO track: operations chief at battalion S-3, regimental S-3, division or MEF; intel chief at S-2; senior MOS-functional billets at TECOM, HQMC manpower (MMPB), SOI / MCRD / TBS senior cadre. Both pin at E-8; the slate determines which billet you walk into. At E-9 the SgtMaj community owns the troop-leadership pinnacle billets (battalion / regimental / division / MEF / MARFOR SgtMaj, HQMC senior enlisted billets, SMMC — the Sergeant Major of the Marine Corps); the MGySgt community owns the occupational SME pinnacle billets (senior 03XX occfield expert at TECOM, HQMC manpower MMPB, senior SOI / MCRD / TBS instructor cadre, the senior MOS roadmap owner roles, and the master gunner billets at division and MARSOC). The Sergeants Major Symposium at Marine Corps University (Quantico) is the institutional gate for the SgtMaj community; the senior occupational track has its own institutional development through TECOM and HQMC. The retirement math at GySgt → MSgt / 1stSgt with 16-22 years TIS is the load-bearing financial decision of late mid-career. The 20-year retirement math under BRS (2.0% per year of service multiplier — 40% at 20, capped per the current retirement system; TSP match accumulating) compounds, and the post-service market for senior 0331 NCOs with clearance and clean record is structurally strong now in the firearms-instruction and training markets specifically. The math: stay for E-8 (1stSgt / MSgt) and 22-24 years TIS to ride the pension up, then potentially compete for E-9 — or EAS at 18-22 years and convert to defense industry / federal LE mid-career.
FAQ

0331 E7 — Frequently Asked Questions

Q01What does a E7 0331 (Machine Gunner) actually do?
You run the company's training and tasking calendar in concert with the 1stSgt and the company commander — for a weapons company that owns the battalion's M240s, M2s, Mk19s, mortars, and assault weapons, or for a rifle company whose weapons platoon you have just walked into as its senior NCO.
Q02What's the most important thing to know as a E7 0331?
Gunnery Sergeant 0331 is the company-level senior NCO tier on the heavy-weapons side — doctrinally weapons company gunnery sergeant (the senior NCO in the battalion's heavy weapons company), company gunny of a rifle company (the company's senior NCO outside the 1stSgt chair), operations chief at battalion S-3 supporting heavy-weapons employment planning, or instructor / cadre billet at SOI / TECOM.
Q03What does a typical day look like for a E7 0331?
Time-blocked day at the E7 0331 rank tier: 0500 Wake. PT gear on. Phone check — overnight company / battalion emergencies. Marine in jail in town? Family deathgram? CO emergency? BN SgtMaj call? You are the senior heavy-weapons NCO the company looks to first. The 1stSgt hears about it as you walk into the company office, 0530 PT formation. You report company gunny accountability to the CO and the 1stSgt; the 1stSgt rolls it up to the BN SgtMaj. The regimental SgtMaj walks the formation occasionally; he reads the company by reading the company gunny and the 1stSgt, 0545-0700 Unit PT.…
Q04What mistakes get E7 0331 soldiers fired or relieved?
Underestimating the SgtMaj-community dynamic in the heavy-weapons community. The 0331 senior NCO community is small and visible — your read at GySgt propagates by name across BNs and regiments; Missing Advanced Course PME. The E-8 board reads PME explicitly; missed gates are visible and there's no recovery within a board cycle; Phoning weapons company gunny role. The weapons company gunny owns the battalion's heavy-weapons combat power;…
Q05What career decisions matter most at the E7 0331 rank tier?
1stSgt vs MSgt fork at E-8 — troop-leadership pinnacle vs staff senior NCO track — The 1stSgt vs MSgt fork at E-8 is the most consequential GySgt-to-E-8 career decision. 1stSgt is the troop-leadership senior NCO (the 8999 1stSgt MOS, requiring the 1stSgt school — verify current school location and duration against MARADMIN): company senior enlisted leader, daily formation, discipline, counseling, climate, family readiness, casualty assistance. MSgt is the staff senior NCO track: operations chief at battalion S-3, regimental S-3, division or MEF; intel chief at S-2;…
Q06What's next after E7 for a 0331 (Machine Gunner) in the Marines?
MSgt / 1stSgt at E-8 is the next gate.
Q07What manuals and regulations does a E7 0331 need to know cold?
The current MCRP 3-10A-series rifle company manual (your operational manual now — guns plus mortars plus assaults plus the rifle squads you support).; The current MCRP 3-15-series machine gun and heavy weapons employment manual (you teach the next generation off this, not consume it).; MCDP 1 — Warfighting; MCDP 1-3 — Tactics.

Based on 25 tips from 0 contributors

Published by the Honest MOS Editorial DeskVerified against DoD/.gov sourcesUpdated May 2026Editorial standards