The reticle editor

Goal of this article: know what the reticle editor is for, when you need it, and how the window is laid out. The three articles after it cover the work itself.

The editor is a separate application in the same folder as the calculator — ReticleEditor.exe on Windows, ReticleEditor on Linux. It creates and edits .reticle files: the reticle definitions the calculator’s reticle view draws your solution onto.

An M16 iron-sight picture mid-edit: the render on the left, parameters, element list and operations on the right, cursor coordinates and the last action in the status bar.

Why it exists

Because the sight picture is only as truthful as the reticle behind it. The reticle view tells you where a hold lands in your reticle — which marks to use, whether a target fits between them, where a moving-target lead sits. All of that is worthless if the marks are on the wrong subtensions.

34 reticles ship in data/reticle: 13 measuring grids (MILDOT, MOA-GRID, H58, Leupold’s CCH and CMR-MIL, six EOTech Vudu patterns, GERMAN4 and an M16 iron sight) and 21 renderings of real optics with their drop ladders — Trijicon ACOGs, V-COGs and Hurons, Elcan Specters, Leupold CMR-W and CM-R², four EOTech Vudus, and the PSO-1. data/reticle/README.md indexes them in two tables, load-calibrated and geometric, and each reticle has a companion .md beside it with the pattern and its calibration in full. They cover the common patterns, but your scope’s reticle is quite possibly not among them, and this is what you use to describe it.

Three other reasons people end up here:

• A simplified reticle to read holds from. A bare cross with marks at the ranges you actually shoot is often more useful on screen than a faithful copy of a busy hunting reticle.
• BDC anchors for your load. A reticle can carry BDC points — positions the calculator labels with distances from the current trajectory. Put them on your reticle’s real marks and the sight picture tells you which mark is 400.
• Iron sights. The shipped M16 picture is an aperture and a post, not a crosshair, and it works the same way.

What it is not

It is not a drawing program. There is no freehand, no dragging, no zoom or pan, and no undo. Every element is described by numbers you type — an angular position, an angular size — and the preview shows the result. That sounds austere, and it is the right trade: a reticle is a measuring instrument, and 1.5 mil means 1.5 mil, not “about here”.

Letting an AI assistant draw it instead

A busy reticle is a lot of typing — a mil-dot grid is dozens of elements, each with its own coordinates. If you use Claude Code or Codex, there is a skill that writes the file for you: reticle-designer, in the original BallisticCalculator repository.

You describe the reticle in plain language — the angular units, the field of view, the central aiming feature, hash spacing, a holdover ladder or wind grid, labels and colours, or simply the name of a commercial reticle to imitate (H58, TReMoR, MOAR) — and it emits a .reticle file in the same BXml format this editor reads, plus an SVG preview and a subtension table to check it against.

Drop the result into data/reticle and it opens here like any other file, so the editor becomes the place you adjust a generated reticle rather than the place you type every element by hand. Worth knowing about before you hand-write the XML yourself: the format ignores what it does not understand, so a typo is a silently missing element rather than an error.

The window

Left	The reticle as it will look, scaled to fit and centred. It redraws after every change
Right, top	Reticle parameters — name, size, zero, and a Set button
Right, middle	The element list, each element spelled out as text (Circle(p=(0mil:0mil),r=6mil,w=0.01mil,c=black))
Right, bottom	The element type dropdown and the operations: New, Edit, Duplicate, Delete, Up, Down
Status bar	The cursor’s angular position, and a message reporting the last action

The splitter between the two halves can be dragged, and its position — along with the window size and the font size — is remembered between sessions.

The View menu holds three things worth knowing about:

• Increase / Decrease Font Size (Ctrl++ / Ctrl+−) — the editor’s own text, useful on a dense element list.
• Coordinate Display Units — Mil, MOA, in/100yd, cm/100m. This changes only the status bar readout, not the reticle. It follows the reticle’s own unit when you open a file.
• Highlight Current Item — draws a magenta halo behind the selected element, several times its own line width, with the element itself redrawn on top in its own colour. That is how you find out which of forty lines you have selected. On by default; turn it off to see the reticle exactly as it will appear. The halo rather than a recolour is deliberate: restating a 0.01 mil hairline as a 0.01 mil hairline in another colour is invisible on a dense reticle, and magenta is used because blue already marks the BDC points in the same preview.

Files

Reticles are XML, saved as .reticle, and both the open and save dialogs start in the data/reticle folder — the same folder the calculator’s Load… button looks in, so anything you save there is immediately available to the sight picture.

Ctrl+N	New — a 10 × 10 mil reticle with zero in the middle
Ctrl+O	Open
Ctrl+S	Save
Ctrl+Shift+S	Save As

Unsaved changes are guarded. File → New, File → Open and closing the window all ask first when the reticle has changes that are not in a file, offering Save, Don’t Save and Cancel. Cancel leaves the drawing exactly as it was; so does picking Save and then cancelling the file picker. The window title carries the file name and an asterisk while there are unsaved changes:

Reticle Editor — mildot.reticle *

The editor has no undo, so Save As before an experiment remains the safe habit — the guard protects you from losing the drawing, not from changing it.

Next

Reticle size and zero — the coordinate space, which has to be set up before any element can be added.

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