How to Call for Fire

Who you are, what kind of mission, and how you're locating the target.

Where it is — plus the direction the FDC needs to apply your corrections.

What it is, how you want it hit, and who says "fire."

A Worked Example — Grid Mission, Adjust Fire

You're the observer, call sign Steel Four-Four. The FDC is Steel One-Six. You've spotted an infantry platoon moving in the open at grid NK180513 and you want mortars on them. Here's the full exchange — your transmissions and the FDC's replies:

OBSERVER  "Steel One-Six, this is Steel Four-Four,
           ADJUST FIRE, over."          <- ID + warning order
FDC        "Steel Four-Four, this is Steel One-Six,
           adjust fire, out."

OBSERVER  "Grid November Kilo one-eight-zero
           five-one-three, over."        <- target location
FDC        "Grid NK one-eight-zero five-one-three, out."

OBSERVER  "Direction five-two-one-zero."  <- OT direction (mils)

OBSERVER  "Infantry platoon in the open,
           at my command, over."          <- description +
FDC        "Infantry platoon in the open,          control
           at my command, out."

FDC        "Message to observer: [guns], in adjustment,
           [rounds], target number Alpha Bravo one-zero-
           zero-one, over."
OBSERVER  "Read back... out."

           ...you call "Steel One-Six, FIRE, over."

FDC        "Shot, over."     OBSERVER "Shot, out."
FDC        "Splash, over."   <- look at the target NOW
OBSERVER  "Right five-zero, drop four-zero-zero, over."  <- bracket
           ...
OBSERVER  "FIRE FOR EFFECT, over."   <- target is bracketed

Note the shape: you never send more than one chunk at a time, you wait for the read-back, and the FDC ends its transmissions with "out." Every mil and grid here is illustrative — your real numbers come off your own map and rangefinder.

Reading a Target Grid

The grid is the part everyone thinks they know until they garble one under stress. The rules are boring on purpose — boring is how the rounds land where you're looking.

• 01A grid coordinate is read RIGHT, then UP — easting first, then northing. Read left-to-right along the bottom, then bottom-to-top up the side. "Right and up" is the whole trick.
• 02Six digits = three for the easting, three for the northing, locating a point to 100 meters (e.g., 180 513). Eight digits (four and four) tightens it to 10 meters.
• 03The two-letter prefix (the 100,000-meter square, e.g., "NK") matters when you're near a grid-zone boundary. Include it in the call so the FDC isn't off by a full grid square.
• 04Read the digits one at a time — "one-eight-zero, five-one-three," not "one hundred eighty." Transpose two numbers and the rounds land a kilometer from where you're looking. This is the single most common way a call for fire goes wrong.

The Adjustment Phase — Bracketing

If you called "adjust fire," the first round is a ranging shot, not the main event. Your job now is to walk it onto the target by correcting along the observer-target line and squeezing a bracket around it. The method is bold, not timid:

1. 01The FDC reads your mission back (the message to observer), then says "Shot" when the round leaves the tube and "Splash" a few seconds before impact. "Splash" is your cue to be looking at the target area — not down at your map.
2. 02Spot the round and correct along the observer-target (OT) line, not relative to yourself. Deviation first: how far left or right of the target the round landed, to the nearest 10 meters ("Right 50," "Left 30").
3. 03Then range: is it over the target or short of it? Make a BOLD correction to throw the next round to the opposite side. Doctrine's standard opening move is add or drop 400 — "Drop 400" — so you get a round short after one that was over. Now you have a 400-meter bracket with the target somewhere inside.
4. 04Split the bracket. Halve your range correction each time: 400 becomes 200, 200 becomes 100. Each round should flip from over to short and back, tightening the box around the target.
5. 05Once you've got the target inside a 100-meter bracket (or a round within 50 meters of it), call "Fire for effect." That's the whole volley, on target. Chasing the round with timid 50-meter creeps instead of bracketing wastes rounds, wastes time, and lets whatever you're shooting at move or dig in.

The Mistakes That Actually Happen

Nobody fails a call for fire because they didn't memorize the doctrine. They fail because they got fast and sloppy at exactly the wrong moment. These are the ones that bite: