Self-AuthoredU.S. Marine Corps2022
The Manual Nobody Asked For
Twenty pages of indirect-fire doctrine, condensed into a teaching reference a Marine would actually sit down with. No one ordered it. It just needed to exist.
- MOS
- 0341 Mortarman
- Billet
- Forward Observer
- Unit
- Weapons Co., 2d Bn, 25th Marines
Scenario
Doctrine exists. Getting a Marine to sit down with it is another story.
My MOS was Mortarman (0341). My billet was Forward Observer at Weapons Company, 2d Battalion, 25th Marines. The Marine on the ground responsible for locating targets and calling for fire from supporting arms. I had just completed the Basic Forward Observation Course through the Marine Corps Institute (MCI) and the Joint Fires course through Joint Knowledge Online (JKO). The procedures were fresh; the source materials were not.
Fire-support doctrine is scattered across field manuals, MCI modules, and JKO coursework: hundreds of pages of dense, reference-style text. Comprehensive. Accurate. Designed to be looked up, not sat down with.
A Marine will read 20 pages. They won't read 400.
The stakes are real. Using the wrong asset at the wrong range costs lives when it eventually matters. But nobody sits down with the primary sources voluntarily. Formal training pushes the material at you once; retention is expected by osmosis.
Drawing primarily on the Basic Forward Observation Procedures MCI, I wrote a condensed reference: something peers could teach from, and something I could use to keep the material sharp. No one asked me to.
Approach
Restructure around the decision, not the subject
Most doctrine is organized by topic: one chapter per asset, one per procedure. I reorganized around the decision a Marine has to make, in sequence.
Which asset fits this target?
Compare trajectory, rate of fire, range, and effect across the four main indirect-fire systems.
Who do I call to get it?
Understand the fire-support team (Forward Observer, Fire Direction Center, Fire Support Coordinator) and the order in which they sequence.
How do I describe the target?
Choose a direction method (OT Line, GT Line, Cardinal, Arbitrary Reference) based on your position and the observer's mobility.
What effect do I want?
Pick between destruction, neutralization, and suppression. Each has different ammunition cost, casualty thresholds, and frequency of use.
The document closes with two fully worked tactical examples: a ground-observer polar mission and an aerial-observer scenario. I built them from commercial satellite imagery of active positions in Ukraine, pulled through Global Enhanced GEOINT Delivery (G-EGD), NGA's imagery distribution platform. Junior Marines learning to call for fire absorb more from current, real terrain than from abstract training aids. That judgment drove the choice. GEOINT data and distribution-restricted identifiers were redacted per caveat requirements.
Assets
Four systems, one decision
The first decision in any fire mission: which asset best fits the target? Each system trades range for rate of fire, precision for coverage, trajectory for terrain tolerance.
Mortars
Light artillery
Trajectory
High
Rate of fire
Up to 20 rounds per minute
Range
Short, must stay near the forward line of troops
Best for
Entrenched or dug-in targets · Reverse-slope positions · Uneven terrain
Howitzers
M777 · 155mm · Medium artillery
Trajectory
Medium, can fire high like a mortar or flat like naval gunfire
Rate of fire
2–3 rounds per minute · massed-fires principle
Range
Medium
Best for
Armored targets · Hardened structures · Dismounted infantry · GPS-precision strikes
Naval gunfire
5-inch / 54 cal · DD-51 · CG-47
Trajectory
Flat, high muzzle velocity
Rate of fire
Up to 20 rounds per minute · 600 rounds per gun onboard
Range
Long · ship-dependent
Best for
Material targets with vertical faces · Direct or assault fire (care required near friendly troops)
HIMARS
M142 rocket system
Trajectory
Medium to low · range-dependent
Rate of fire
1–6 rockets per pod · minutes to reload
Range
2–300 km depending on munition
Best for
Precision targets · Large troop concentrations · Hardened structures and bunkers
Desired effect
Three ways to define success
Destruction
Threshold
Target destroyed, or 30%+ casualties
Cost
High · precision adjustments and heavy ammunition expenditure
Frequency
Rarely fired · must be well-justified
Neutralization
Threshold
Combat effectiveness disrupted · roughly 10%+ casualties
Cost
Low · correct shell/fuze combination
Frequency
Most common fire mission
Suppression
Threshold
Hostile element temporarily stops functioning
Cost
Low
Frequency
Limited · no lasting effect on most targets
Call for fire
Five transmissions between observer and gun
A call for fire is a scripted exchange. Every line has a purpose: establishing position, warning the supporting arm, committing to the mission, describing the target, closing the loop.
- 01
Position report
FO → FDCFDC // FO — Standby POSREP — OVER.
Observer provides current and accurate grid position.
- 02
Warning order
FO → FDCFDC // FO — Standby Call for Fire / Adjust Fire — OVER.
A fire mission is about to commence. Supporting arm goes ready.
- 03
Fire mission
FO → FDCFDC // FO — Adjust Fire Polar — Direction 3644 — Distance 880m — OVER.
Polar mission: direction in mils plus distance. No target grid required.
- 04
Target & shell/fuze
FO → FDCTARGET description + Shell/Fuze (e.g., half-quick / half-delay) — OVER.
This is a request. The FSO has final call on how to engage.
- 05
MTO readback
FDC → FOREAD BACK THE MTO VERBATIM.
FDC issues a Message to Observer: firing unit, rounds in adjust, rounds in effect, target number. Repeat it word-for-word.
Direction
Four ways to point at a target
How you describe direction depends on who you are and where you are. A stationary ground observer uses one method; an orbiting drone needs a different one.
OT Line
Observer-Target LineAn imaginary line from the observer, through the target.
Use when
Stationary ground observer with line-of-sight. Most common method for target location and adjustment.
GT Line
Gun-Target LineAn imaginary line from the firing unit, through the target.
Use when
Aerial observer (drone or helicopter). The observer's orientation relative to the target is constantly shifting.
Cardinal
Cardinal / IntercardinalThe eight compass directions (N, NE, E, SE, S, SW, W, NW).
Use when
No compass, no map. Least accurate method, used only when precision tools are unavailable.
ARF
Arbitrary Reference FeatureA natural or manmade feature referenced for target location and fire adjustment.
Use when
When transmitting OT Line would compromise the observer's position.
Translation
Knowledge management, with the stakes made literal
Strip away the jargon and this was a content problem: dense reference material, restructured into something a reader would actually open.
Marine Corps context
Civilian equivalent
Field manuals that cover everything and teach nothing
Internal wikis that document everything and onboard no one
Formal training that fades after the course ends
Onboarding that fades by week three
Tacit NCO knowledge about which asset to call
Tribal knowledge about which runbook to reach for
A condensed reference a Marine would actually sit down with
A one-pager a new hire would actually open
The work is the same. The stakes are just quieter.
Takeaway
What the project taught me
Rank doesn't gate clarity
A Lance Corporal writing reference material could seem out of place. But the people closest to how a document actually gets used are often best positioned to improve it. Nobody asked me to write this. The document justified itself.
Structure follows decisions, not topics
Doctrine tends to organize by subject. One chapter per asset, one per procedure. I reorganized around the decision a Marine has to make, in sequence: which asset, who to call, how to describe, what effect. The information didn't change. The order did.
Writing for voluntary readers is a skill
Primary sources earn their bulk by being thorough. They're designed to be looked up, not worked through. If you want people to actually engage with technical material, length and hierarchy matter more than coverage. That discipline transfers directly to any internal document you want opened, not archived.