The ranging tool sits in the app's Tools section alongside the clinometer and the compass. You give it a target dimension and the angle that dimension subtends in your reticle, and it returns the distance — then offers to put that distance straight into the calculator.
Using it
- Open Tools and choose the ranging tabSet the angular unit first — MIL or MOA — to match the reticle you are measuring in.
- Enter the target's real sizeType it, or use one of the presets: a standing person at 1.8 m, a torso at 0.5 m, an IPSC target at 0.45 m, or a deer at 0.4 m.
- Measure the target in the reticleBracket the same dimension you entered — height against height, width against width — and read it to the nearest tenth.
- Enter the measured subtensionThe distance appears immediately.
- Send it to the calculatorOne tap moves the ranged distance into the solution rather than you retyping it.
The arithmetic, if you want to do it yourself
With MIL: distance in metres equals target size in millimetres divided by the measured mils. A 1,800 mm person subtending 3.0 mils is at 600 m.
With MOA: distance in yards equals target size in inches times 95.5, divided by the measured MOA. Workable on paper, awkward in the field — which is why MIL is the more common choice among shooters who range this way.
Where the error comes from
| Source | Effect | Mitigation |
|---|---|---|
| Wrong assumed target size | Proportional error in distance | Range off objects of verified size, not off animals |
| Reading to the nearest half mil | Large at long range | Read to a tenth; use the finest stadia you have |
| Second focal plane at wrong magnification | Wholesale error | Return to the calibrated magnification first |
| Unstable position | Wobble makes bracketing imprecise | Range from support wherever possible |
| Small subtension | Error grows as the target gets smaller | Prefer larger reference objects near the target |
The dominant error is almost always the assumed size. A tenth of a mil misread is a few per cent; a deer assumed 20 per cent larger than it is puts you 20 per cent long, every time, with no way to notice.
Ranging off something else
A useful field habit: range off a nearby object whose size you genuinely know rather than off the target itself. A fence post, a gate, a vehicle, a standard steel plate, a hay bale. If it is close to the target and you know its dimension, it is a better reference than an animal whose size you are estimating.
Checking yourself against a laser
The way to trust reticle ranging is to have measured your own error. Range a target with the reticle, write the number down, then laser it. Do that across a session and you learn both the size of your error and whether it is biased long or short.
The structured version, with a scoring table and a pass mark, is the unknown distance drill.
When not to use it
- When you have a working laser and a clear line. The laser is more precise; use the reticle as the backup it is.
- On targets of unknown size. You are not ranging, you are guessing with extra steps.
- Beyond about 800 m on human-sized targets. The subtension is too small to read to useful precision.
- From an unstable position, if precision matters. Wobble dominates the measurement.
Frequently asked
Does this work with a second focal plane scope? +
Only at the magnification the reticle is calibrated for, usually maximum. At any other setting the subtensions are wrong and so is the range.
Which is better for ranging, MIL or MOA? +
MIL, because a mil subtends one thousandth of the distance and the arithmetic collapses to a division you can do in your head. MOA works but needs a conversion constant.
Can I range off a deer? +
You can, but body sizes vary enough that the assumed dimension carries real uncertainty. Prefer an object of verified size near the animal.