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0341E4

Mortarman

E-4 (Specialist/Corporal) · Marines

E1–E3E-4E-5E-6E-7E8–E9
HEADS UP

You pinned Corporal and stepped to the gun team leader seat. The section leader is no longer checking your fire commands — that is your job now. The fire mission is yours, the crew is yours, and the FitRep the section leader writes on you tracks directly whether you ran the crew like an NCO or like a promoted LCpl waiting to be told what to do.

The Honest MOS Read
Corporal is the rank where the Marine Corps separates the NCO from the promoted lance corporal. The gun team leader billet at Cpl is the first command position in the 0341 career path — not command in the officer sense, but command in the only sense that matters on the gun line: the tube fires when you say it fires, the crew knows what to do because you have drilled them, and the fire command data is verified before the round goes in the tube because you checked it and not because someone checked behind you. The section leader is watching whether you are running the gun team or the gun team is running itself while you stand nearby. The Corporals Course is the PME gate that formally opens the NCO lane. It is typically delivered at the unit level under the SgtMaj's supervision or at a regional Marine Corps NCO Academy, and it covers NCO leadership responsibilities, the Uniform Code of Military Justice basics, the counseling framework under MCO 1610.7 (Marine Corps Performance Evaluation System), and the administrative tools a Cpl uses to document and develop junior Marines. The Corporals Course is not optional and it is not a formality — the SgtMaj of the battalion tracks which Cpls have completed it, and the section leader's FitRep on you references it. Complete it early. Do not wait for someone to schedule you. The composite score race for Sergeant is the background context for everything you do as a Cpl. The TFRS (Total Force Retention System) cutting scores for 0341 are published in periodic MARADMIN messages and vary with retention needs — they are not static, they are not predictable, and a cutting score that was 1680 last year may be 1720 this year or 1650 next year. What is static is the formula: PFT points + CFT points + rifle qualification score + MCMAP belt value + education credits + time-in-grade + time-in-service. The Cpl who has been stacking those inputs since LCpl finds the cutting score reachable from his current composite. The Cpl who coasted through the boot years is behind before the race starts. On the gun line, the Cpl gun team leader's technical job is the gunner slot plus the leadership layer. You are running the deflection and elevation from the FDC data, verifying the fire command against the safety template data before calling 'READY,' ensuring the propellant lot is matched and the charge is correct before the A-gunner's hands reach the tube, and calling the time-of-flight sequence — "HANG," "SHOT," "SPLASH" — in synchronization with the FDC's tracking. The section leader is watching your crew timing, your crew communications, and how you handle the fire command when the data comes in wrong. When the FDC sends a deflection that puts the round outside the safety template, you are the one who catches it and calls "CHECK FIRE" before the round moves toward the tube. The Marine who lets a bad fire command through because he did not want to question the FDC is the Marine the safety officer's report names. The MEU workup and deployment cycle as a Cpl gun team leader looks materially different from the boot years. You are now one of the leaders the platoon sergeant and section chief are evaluating during the MEU-SOC certification events. Your crew's drill time, your crew's ammunition accountability, and your crew's maintenance posture are on the section chief's radar as inputs to the collective MCCRE grade and the MEU certification packet. When the section chief debrefs the section after a fire mission lane, he is talking to you — not over your head to the A-gunner. The relationship with the section chief is now a peer NCO relationship in the direction of development; the section chief is not babysitting you, he is mentoring you toward the section leader seat, and the mentoring is calibrated by how seriously you take the gun team leader billet.
Career Arc
  • 01Pin Cpl — step to the gun team leader seat. Complete Corporals Course at the earliest available slot.
  • 02First six months as a Cpl: own the gun team's maintenance posture, crew drill timing, and ammunition accountability. Get on the section chief's radar as the gun team leader who runs his crew without daily management.
  • 03Composite score tracking: PFT and CFT scores, rifle qualification, MCMAP belt progression, education credits via CLEP/TA — stack every input systematically because the TFRS cutting score does not care about effort, only about points.
  • 04MEU workup as a gun team leader: MEU-SOC certification evaluation, section chief's performance input into the FitRep cycle, and the collective MCCRE grade that reflects your crew's proficiency.
  • 05Sergeants Course eligibility approaches — the section chief recommends you by name. If you have not been recommended by thirty months as a Cpl, have the direct conversation with the section chief about what is missing.
Common Screwups
  • ×Running the gun team like a promoted LCpl — continuing to wait for the section leader to initiate crew drill, gear inspection, and maintenance checks rather than driving the team's readiness independently. The section leader is watching whether you took ownership of the gun team or whether you are still waiting for direction. The Cpl who needs to be told to inspect the tube before stand-to is not running a gun team; he is following one.
  • ×Letting a bad fire command through without calling 'CHECK FIRE' because you did not want to appear to question the FDC. The gun team leader's authority to call 'CHECK FIRE' is absolute and non-negotiable. A deflection or elevation that puts the round outside the safety template is a safety incident in progress — your job is to stop it before the round moves. The FDC expects the gun team leader to catch their errors; a section chief who sees a gun team leader hesitate on a 'CHECK FIRE' call has written the next counseling statement in his head.
  • ×Composite score neglect — arriving at eighteen months as a Cpl with a PFT score that has not improved since boot camp, a rifle qualification of Sharpshooter, no MCMAP belt progression past the initial award, and zero TA credits. The cutting score for 0341 Sgt may move up or down but your composite inputs are fully within your control. The Cpl who discovers the gap at month twenty-four cannot close it in time; the Cpl who has been stacking inputs from month one finds the Sgt promotion conversation is about timing, not eligibility.
  • ×FitRep cycle blindness — not understanding that the section leader's FitRep on you is the primary document MMPB (Manpower Management Personnel Branch) uses to evaluate your promotion eligibility and B-billet candidacy. The FitRep under MCO 1610.7 covers leadership, duty performance, and professional military education. A Cpl who has not counseled his junior Marines on paper, not completed Corporals Course, and not driven his crew's MCCRE lane performance is giving the section leader nothing to mark in the top-third of the reporting seniors.

A Day in the Life

  • 0445Up before formation. Check the section's group chat for any overnight tasking or incidents involving your Marines. Verify your two-man crew's accountability — if one of them is on duty or had liberty issues overnight, you know before the section chief asks.
  • 0530PT formation. As a Cpl gun team leader you are standing at the front of your crew, not behind the section leader. You report your crew's accountability to the section chief. Anyone missing or in a modified PT status is reported by you, with the reason, before the platoon sergeant asks.
  • 0545-0700Unit PT — you are running the same physical standard as your Marines, not setting a lower pace because you have the chevrons. The gun team leader who coasts on PT is invisible to the crew in the wrong way. Weighted humps are the section's primary PT event; the gun team leader carries the gun team's load share without making it a commentary.
  • 0700-0830Hygiene, utilities, chow. Before morning formation, pre-walk the weapons bay — tube, bipod, sight unit, cleaning rod set. The section chief will check. You check first.
  • 0830Morning work formation. Section chief gives the day's tasking. You receive it, translate it into your crew's specific tasks, and brief your two Marines before they walk to the work area. 'We are doing tube maintenance this morning, then a crew drill block before chow. I will inspect the tube before the section chief does.' That sentence.
  • 0900-1130Work block. Tube maintenance to the pre-combat inspection standard. After maintenance, run the fire mission crew drill: FDC data card, deflection-elevation set, charge and lot verification, READY-HANG-SHOT sequence — timed, graded by you, and logged. The section chief walks through and watches; you are running the drill, not performing for him.
  • 1130-1300Chow. You eat with your crew and the other gun team leaders. The conversations at this table are different from the boot table — section operations, MCCRE prep, composite score math, who is going to Sergeants Course, who needs to be counseled. The platoon sergeant is not at this table but he knows what was discussed.
  • 1300-1500Afternoon block — section chief's tasking: FDC data exercise, range prep, map reading drill, administrative work (counseling binder entries, composite score tracking, Corporals Course scheduling if not complete). The gun team leader who uses administrative time to actually close administrative tasks is the one whose FitRep does not have open items at the reporting period close.
  • 1500-1630Final formation, sensitive items accountability, next day's plan. You brief your crew on tomorrow's uniform, gear, and accountability requirements before liberty call. No Marine in your crew is calling you at 0430 to ask what time formation is.
  • 1630-1700Liberty call. On a normal garrison day. You verify your crew is in a liberty-worthy posture — no pending NJP, no medical limited duty violations, no gear accountability gaps — before you leave the company area.
  • MCCRE / fire mission evaluationClock compresses. Your gun team is at the firing line before the section chief has to prompt. Aiming stakes in. Tube bore-sighted. Sight unit collimated. Fire command data card ready at the gun team leader position. When the FDC sends data, you run the verification sequence aloud, every step, in order. The section chief is standing five meters behind you taking notes. The crew knows what to do because you ran this drill in garrison for the last eight weeks.

Weekly Cadence

The garrison week as a Cpl gun team leader runs on two calendars simultaneously: the company training schedule the section chief briefs at Monday morning formation, and the personal administrative calendar you are managing for the gun team's composite score inputs, counseling binder entries, and PME completion. Monday morning is the hardest accountability check — any liberty incidents from the weekend surface through the company duty officer's report, the section chief has already read it before you arrive, and the gun team leader whose Marine is in that report is getting counseled before the day's training begins. The gun team leader who calls the section chief on Sunday evening with 'Cpl [name] was stopped by base MP last night, I have the facts, here is what happened' is the one the section chief respects on Monday morning. The gun team leader who hears about it for the first time at formation is the one who spent the weekend not tracking his Marines. Tuesday through Thursday is the rhythm of crew drill repetitions, range prep, administrative work, and whatever combined-arms or supporting-arms integration training the company schedule includes. The section chief reads the composite score inputs for every Cpl in the section at least quarterly — he knows who is at cutting score and who is not. The gun team leader who asks the section chief 'what inputs are you seeing me miss' at the three-month mark as a Cpl is the one who closes the gaps before they compound. Friday is the lightest scheduled training day in most garrison battalions; it is also the day the section chief runs informal performance conversations with his gun team leaders before the weekend. Be present, be available, and have the composite score math current before that conversation.

Key Skills — How to Drill Each

  1. 01
    Run the complete gun team leader fire command verification sequence — receive FDC data, verify deflection and elevation against the safety template, verify charge and lot, call 'READY,' and call time-of-flight sequence — without the section leader standing behind the gun.
    The verification sequence is a checklist that the gun team leader runs aloud, in order, every fire mission: FDC data received and repeated back, deflection cross-checked against the safety template azimuth limits, elevation cross-checked against max ordinate and minimum safe altitude restrictions if applicable, charge selected and lot verified against the authorized lot number board at the gun position, 'READY' called to the FDC only after all four checks pass. Run this sequence in garrison dry-fire until it is automatic under noise, under time pressure, and when the first data card looks slightly wrong. The section chief stands behind the gun on fire mission evaluations; he is watching your verification sequence, not your crew's.
  2. 02
    Counsel junior Marines in writing under the MCO 1610.7 framework — performance counseling, corrective counseling, and mid-cycle performance review — and retain the paper trail.
    The counseling binder is the gun team leader's administrative responsibility from the moment of assuming the billet. Every Pvt and LCpl in your crew gets a performance counseling entry at the beginning of the FitRep cycle and a corrective counseling entry any time performance, conduct, or standards require it. The section leader reviews the counseling entries when he writes your FitRep — a Cpl who cannot produce a counseling binder for his Marines is a Cpl who, in the section leader's documented assessment, is not executing the NCO leadership responsibilities the billet requires. Pull the current MCO 1610.7 and read the counseling chapter; the section leader is not teaching it to you one step at a time.
  3. 03
    FDC mathematics basics — computing firing data from map and registration data, converting grid azimuths to deflections, and identifying when FDC-computed data is out of bounds for the gun position.
    The Cpl gun team leader who understands FDC mathematics is the one who catches the transposition error before the round goes down range. You do not need to be the FDC chief — you need enough working knowledge to cross-check the deflection and elevation the FDC sends against the map, the known reference point data, and the safety template. Run map-to-deflection conversion exercises with the section chief using historical fire mission data. The 0341 who understands both ends of the fire mission — the tube and the FDC — is the one the section chief recommends for FDC certification at Sgt.
  4. 04
    Run a vehicle- or crew-served-equipment PMCS (Preventive Maintenance Checks and Services) to the Marine Corps standard — M252A2 systems checks, M1114 or 7-ton pre-combat check, and the section's optics and communications gear accountability.
    The gun team leader is responsible for the maintenance posture of everything the gun team is issued. The M252A2 bipod clamp tension, the M64A1 sight unit collimation, the baseplate impact plate inspection for stress fractures, the cleaning rod segment count, and the breech plug O-ring condition are the gun team leader's accountability items on every pre-combat check and every post-operation inspection. A section chief who finds a cracked baseplate impact plate during a pre-deployment inspection — that the gun team leader did not find — is writing a counseling statement, not a teaching moment.

Manuals & References — What Chapters Matter

  • MCO 1610.7 — Marine Corps Performance Evaluation System.
    This order governs FitRep administration, counseling requirements, and the performance evaluation framework that the section leader uses to document your performance as a Cpl gun team leader. The counseling chapter specifies what a Cpl is required to do for his junior Marines, how often, and in what format. The Cpl who reads MCO 1610.7 before the section leader has to explain it is the Cpl who runs the counseling binder without being managed through it.
  • NAVMC 3500.44 — Infantry Training and Readiness Manual (0341 collective and individual tasks, Cpl tier).
    The Cpl-tier task list in the T&R manual includes the gun team leader tasks — fire mission verification, safety template administration, crew drill supervision, and pre-combat inspection standards. The MCCRE fire mission lane at the Cpl tier evaluates these tasks by name. Know which tasks are on your evaluation before the lane, not during it.
  • MCO 1400.32 — Marine Corps Enlisted Promotion Manual.
    This is the governing order for how the composite score is computed, what TFRS cutting scores mean, and how the Sgt promotion process works for active-duty enlisted Marines. Pull it before you sit with the career planner. The planner has a version; so does the battalion S-1 office. Read the composite score computation tables and verify your personal inputs against the order's formula, not against what someone told you at the smoke pit.
  • Current 0341 TFRS cutting score MARADMIN — published periodically by MMPR (Manpower Management Promotion Branch).
    The cutting score for 0341 Sergeant is not a fixed number — it changes with retention supply and demand. The current cutting score is published in an active MARADMIN message; find it on the MARADMIN archive before any promotion conversation. The composite score you have today versus the current cutting score is your gap analysis. If the gap is 40 points, you know what inputs to drive. If the gap is 200 points and your EAS is in eight months, the conversation changes.

Standards — How to Hit Each

  • FitRep in the top-third of the section leader's reporting seniors — documented through crew drill performance, MCCRE results, counseling binder execution, and Corporals Course completion.
    The section leader distributes his FitRep markings across his Cpls; the top-third mark goes to the Cpl whose gun team is the best-performing and whose NCO administrative execution is cleanest. Run the gun team at a level where the section leader can describe specific performance incidents in the FitRep narrative — 'During the MEU-SOC certification fire mission, Cpl [name]'s crew achieved the section's fastest hang-to-shot timing and called CHECK FIRE on the only safety-template-violation data card of the evaluation.' That specificity is only available if you actually performed at that level.
  • Composite score at or above the current TFRS cutting score for 0341 Sgt by the end of the second year as a Cpl.
    PFT and CFT 1st-Class scores lock in the maximum physical fitness composite points — run and train to 1st-Class and stay there. Expert rifle qualification adds more points than Sharpshooter; dry-fire and shoot Expert every cycle. MCMAP brown belt or above adds a belt-value point increment above the initial award — schedule the tape with the section's instructor and complete it. TA credits through MCI (Marine Corps Institute) or CLEP exam add education-level points on the composite formula. Run the formula on your current inputs against the published cutting score twice a year; close the gap intentionally.
  • Corporals Course complete and documented in the service record book before the twelve-month mark as a Cpl.
    The Corporals Course is a PME requirement, not an elective. The SgtMaj's office and the battalion S-1 track completion status. The section leader references it in the FitRep narrative. Complete it in the first available slot after pinning Cpl — do not wait for a convenient moment. If the unit does not have a scheduled course in the next sixty days, ask the section chief where the nearest regional offering is and request the slot.

Technical Mistakes — Concrete Consequences

  • Calling 'READY' to the FDC without completing the full verification sequence — rushing through the deflection and safety template cross-check because the section chief is watching the clock.
    One round outside the safety template on a live-fire event is an immediate range suspension, a safety incident report, and a review board convened at the battalion level that asks the gun team leader to reconstruct the verification sequence step by step. 'I checked it but I was moving fast' is not an answer the board accepts. The section chief who sees a gun team leader shortcut the verification sequence on a training event writes a corrective counseling entry that stays in the service record book and surfaces at every promotion board.
  • Failing to maintain the counseling binder for junior Marines — documenting nothing, counseling verbally only, and producing no paper trail when a junior Marine's performance or conduct requires administrative action.
    When the section leader needs to initiate corrective action on a Pvt or LCpl in your gun team — an NJP referral, a period of limited duty, or a formal counseling that becomes part of a separation package — he asks the Cpl gun team leader for the counseling binder. A binder with no entries tells the section leader and the company 1stSgt that the NCO did not execute the administrative responsibility the billet requires. The subsequent FitRep notation is not a detail.
  • Treating the FitRep cycle as something that happens to you rather than something you drive — not tracking your own composite score inputs, not completing PME on schedule, and not having the performance conversation with the section chief before the FitRep is submitted.
    The FitRep submitted by the section leader is the primary document MMPB uses for promotion eligibility and B-billet screening. A Cpl who has not reviewed his own composite score, has not completed Corporals Course, and has not had the mid-cycle performance conversation with the section chief before the reporting period closes is a Cpl reading his FitRep for the first time after it is already in the permanent record. The section leader cannot retroactively upgrade a submitted FitRep because the Marine finally got interested in his career.

Career Decisions at This Rank

  • Drive composite score inputs toward the TFRS cutting score for Sgt on the current timeline, or accept that the Sgt timeline will extend
    The TFRS cutting score for 0341 Sgt is the only hard number in the promotion equation that you cannot negotiate. Every other input — PFT, CFT, rifle score, MCMAP, education credits, FitRep markings — is within your direct control during the Cpl years. The Cpl who runs the composite score formula on his actual inputs against the current cutting score at the six-month mark as a Cpl has roughly eighteen months to close whatever gap exists before the typical Cpl-to-Sgt window. The Cpl who first runs the formula at twenty-four months as a Cpl is managing a compressed timeline with the same fixed inputs. Stack the inputs from day one; the cutting score does not care about your intentions.
  • Request FDC certification track or continue as a gun team leader toward the section leader billet
    The FDC chief role at Sgt is the highest-complexity individual contributor position in the mortar section — the Marine who computes firing data, maintains the registration data, runs the fire mission net, and is accountable for every round's computed trajectory. FDC certification as a Cpl is the prerequisite. The gun team leader who has demonstrated the mathematical aptitude and the attention-to-detail discipline the section chief is looking for will be offered the FDC track before Sgt. If the section chief has not mentioned it by month eighteen as a Cpl, ask directly whether you are on the FDC track consideration list and what you would need to demonstrate to get there.
  • Pursue a B-billet (Drill Instructor, Marine Security Guard, Recruiting) after the current assignment or stay on the gun line through Sgt
    B-billets at the Cpl–Sgt transition are competitive and selective. Drill Instructor school at Parris Island or San Diego, Marine Security Guard duty at FAST Company, and Recruiting duty all require screening, command endorsement, and a clean service record. The FitRep package matters enormously — a Cpl whose FitReps show consistent top-third markings and who has demonstrated the kind of NCO leadership the section chief can describe specifically is a competitive B-billet candidate. B-billets add a dimension to the service record that straight gun-line Sgts do not have; the Marine who has been a DI is taken seriously in a different way when he returns to the weapons platoon. The honest calculus: B-billets are demanding personally and professionally, the separation from the tactical MOS is real, and the return transition requires reintegration. Talk to Sgts who have done it.

How the Seat Varies by Unit Type

  • Infantry battalion weapons platoon (gun team leader)
    The default Cpl assignment — leading a two-Marine gun crew in the weapons platoon of a rifle battalion. The section chief is a Sgt or SSgt who reads every gun team leader's crew drill timing and MCCRE performance. The platoon sergeant is a SSgt who reads every Cpl's composite score and FitRep cycle. The battalion SgtMaj knows every Cpl's name and his counseling binder status by the six-month mark. The MEU PTP workup evaluation at the Cpl tier is the most externally visible performance event in the Cpl's service record for the year it occurs — the MEU-SOC certification board sees the section's collective result and the section chief's individual FitRep on each gun team leader traces directly to it.
  • MEU BLT mortar section
    On the MEU deployment as a Cpl gun team leader, the operational tempo compresses every garrison administrative task into whatever time is not occupied by the contingency response posture, the ship's training schedule, and port call liberty management. Counseling binder entries get written in a ship's compartment at 2200. Composite score MCI coursework gets done between watch rotations. The Cpl who has a clean administrative posture before the MEU deployment begins finds the afloat phase manageable; the Cpl who has open counseling requirements, an unscheduled MCMAP test, and a composite score gap when the ship departs does not close those gaps at sea.
  • UDP Okinawa weapons platoon
    The UDP rotation to Okinawa as a Cpl gun team leader means operating in a III MEF forward-deployed posture with a reduced administrative support infrastructure. The S-1 shop is smaller, the career planner is managing a larger Cpl population with less personal attention time, and the cutting score MARADMIN is still current whether or not someone in Okinawa mentions it. The Cpl who manages his own composite score inputs and FitRep cycle without requiring the career planner to chase him is the Cpl who does not miss a promotion cycle because of administrative gaps that could have been closed from Okinawa.
  • FO/FDC pipeline track (0341 toward fire support)
    Some Cpls are identified by their section chiefs as FDC-track candidates based on mathematical aptitude, attention-to-detail performance on fire mission lanes, and the section chief's read of where the Marine's ceiling is. FDC certification at Cpl opens the section leader FDC chief billet at Sgt and the fire support coordination pipeline beyond that. The Cpl on the FDC track is doing additional work — computing firing data from map exercises, running FDC net procedures in garrison, cross-training on the section chief's position — that the pure gun team leader is not doing. The section chief manages this track informally; if you are not being asked to do additional FDC work, you are not on the track. Ask.

What Good Looks Like at This Rank

The Cpl gun team leader who is doing the job well is the one the section chief mentions to the platoon sergeant before the MEU-SOC certification cycle begins — not because the section chief is managing expectations, but because he already knows what the gun team's certification result will be. The crew runs the fire mission drill in garrison without the gun team leader having to initiate it, because the gun team leader established that expectation in the first week. The counseling binder for every Marine in the crew is current, documented, and retrievable in under sixty seconds. The composite score inputs — PFT, CFT, rifle qualification, MCMAP belt, education credits — are being stacked systematically, not reactively. When the section leader checks the gun team's maintenance posture during a snap inspection, he does not find anything the gun team leader has not already found and corrected. The FitRep the section leader writes on the effective Cpl gun team leader contains specific performance incidents — named events, named results — because the Marine performed at a level that generated those incidents. The section chief can recommend the Cpl for Sergeants Course with a clear conscience because the section chief has watched the Marine run an NCO billet, not a senior LCpl billet with chevrons attached. The gap between a Cpl who gets recommended for Sergeants Course at eighteen months and a Cpl who does not get recommended at thirty-six months is not talent — it is whether the Marine decided to own the gun team leader billet from the first day or whether he waited to see if someone would eventually hand him more responsibility.

Preview — The Next Rank

Sergeant as a 0341 is the section leader billet — three gun teams, a section FDC, and the Marine who is responsible to the platoon sergeant for everything the mortar section does and fails to do. The Sgt section leader is not the senior gun team leader with extra chevrons. He is the Marine who writes FitReps on the Cpls in the section, who runs the section's administrative machinery, and who is the platoon sergeant's primary execution agent for every fire mission, every maintenance cycle, and every MCCRE evaluation the section runs. The gap between Cpl gun team leader and Sgt section leader is not primarily technical — the fire mission skills transfer — it is organizational. The Sgt is managing three crews simultaneously, writing counseling entries for six Marines, running the section's composite score tracking, and giving the platoon sergeant a clear picture of where the section is and where it needs work. Sergeants Course is the PME gate — a resident course delivered at a Marine Corps NCO Academy that covers advanced NCO leadership, military justice administration, and the administrative and operational responsibilities of the Sgt billet. The section chief's recommendation to the Sergeants Course is based entirely on what the Cpl has demonstrated in the gun team leader billet. The Marine who has run a clean gun team, stacked his composite score inputs, and demonstrated FitRep-worthy performance is the Marine the section chief recommends by name. The Sgt promotion itself depends on the composite score meeting the TFRS cutting score — the FitRep and the Sergeants Course recommendation open the door, the cutting score is the key.
FAQ

0341 E4 — Frequently Asked Questions

Q01What does a E4 0341 (Mortarman) actually do?
You own a gun team — the tube, the crew, and the mathematics — and you are responsible for their training, their gear, their conduct on liberty, and their accuracy on every fire mission the FDC sends down the line.
Q02What's the most important thing to know as a E4 0341?
You pinned Corporal and stepped to the gun team leader seat.
Q03What does a typical day look like for a E4 0341?
Time-blocked day at the E4 0341 rank tier: 0445 Up before formation. Check the section's group chat for any overnight tasking or incidents involving your Marines. Verify your two-man crew's accountability — if one of them is on duty or had liberty issues overnight, you know before the section chief asks, 0530 PT formation. As a Cpl gun team leader you are standing at the front of your crew, not behind the section leader. You report your crew's accountability to the section chief. Anyone missing or in a modified PT status is reported by you, with the reason, before the platoon sergeant asks,…
Q04What mistakes get E4 0341 soldiers fired or relieved?
Running the gun team like a promoted LCpl — continuing to wait for the section leader to initiate crew drill, gear inspection, and maintenance checks rather than driving the team's readiness independently. The section leader is watching whether you took ownership of the gun team or whether you are still waiting for direction. The Cpl who needs to be told to inspect the tube before stand-to is not running a gun team; he is following one;…
Q05What career decisions matter most at the E4 0341 rank tier?
Drive composite score inputs toward the TFRS cutting score for Sgt on the current timeline, or accept that the Sgt timeline will extend — The TFRS cutting score for 0341 Sgt is the only hard number in the promotion equation that you cannot negotiate. Every other input — PFT, CFT, rifle score, MCMAP, education credits, FitRep markings — is within your direct control during the Cpl years.…
Q06What's next after E4 for a 0341 (Mortarman) in the Marines?
Sergeant as a 0341 is the section leader billet — three gun teams, a section FDC, and the Marine who is responsible to the platoon sergeant for everything the mortar section does and fails to do.
Q07What manuals and regulations does a E4 0341 need to know cold?
NAVMC 3500.44 — Infantry T&R (Cpl / Sgt 0341 collective tasks; this is the document the section leader quotes back to you on position construction and fire mission execution).; The current MCWP / MCRP covering mortar employment — fire commands, FDC procedures, safety template, registration and adjustment (own it; the platoon sergeant will quote it).; MCRP 3-10A.3 — Marine Rifle Squad (the unit you are supporting, the scheme of maneuver you are integrating into).

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