How to use Within Range

← Back to the calculator

Using the calculator

1. Choose a cartridge. Every load in the list is a hunting-intent projectile; a load's specification and evidence are linked in the assumptions panel once you calculate.
2. Choose a species. This sets the vital-zone proxy and the context-only impact-energy reference used on the chart.
3. Enter your group size, in MOA, and how many shots were in it. Use a real group you shot recently, not a manufacturer accuracy claim. Practice can record this for you and prefill the form.
4. Select the position you shot that group from. The model records this as context; it does not currently apply a position penalty, because no sourced field-dispersion coefficient exists per position yet (see Methodology).
5. Enter wind speed and your uncertainty in that estimate. If you leave uncertainty blank, it defaults to half your wind speed. The form tells you when it has done this.
6. Set your confidence target (default 90%) and, if relevant, altitude and temperature for air density.
7. Read the result. The headline states the binding range and whether it is precision-limited or energy-limited. The chart and table show both curves across the full range. The assumptions panel, open by default, lists every input and source used.

Add to your home screen

Within Range is a normal website, not an app-store app. Adding it to your home screen creates a shortcut with the Within Range icon that opens straight to the calculator, useful for a carpark before a hunt. After you've visited the site once with a signal, the calculator, DOPE table and your saved practice data keep working with no signal, whether or not you've added a home screen shortcut.

iPhone or iPad (Safari)

1. Open withinrange.nz in Safari.
2. Tap the Share icon (the square with an arrow pointing up).
3. Scroll down and tap Add to Home Screen.
4. Confirm the name and tap Add.

Android (Chrome)

1. Open the site in Chrome.
2. Tap the ⋮ menu in the top right.
3. Tap Add to Home screen (sometimes shown as Install app).
4. Confirm the name and tap Add.

Desktop (Chrome or Edge)

1. Open the site.
2. Click the install icon in the address bar (a small screen with a downward arrow), or open the browser menu and choose Install Within Range…
3. Confirm Install.

FAQ

Is this legal or safety advice?

No. The calculator's output is a model result under stated assumptions, not a guarantee, a certification, or a substitute for your own judgement. See the Methodology page for what the model does and does not cover.

What is a "vital-zone proxy"?

A simplified circle standing in for an animal's heart-lung region, used to convert your group size into a placement probability at each range. Its diameter comes from the species data (see Methodology » Vital-zone proxies for how directly each species' value is sourced). It is a modelling simplification, not an anatomical guide, and it does not change shape for a quartering or frontal shot presentation.

Why is impact energy shown if it doesn't set the result?

Because it is a familiar reference point, not because it is a validated humane-outcome threshold. The dataset's energy figures are legal or informal conventions (see Methodology » Where the numbers come from), so only the placement-confidence curve can bind the calculator's result.

Why doesn't shooting position change the result?

Position is recorded as context because no sourced, field-measured dispersion penalty per position currently exists for this model. Adding an invented number would make the result look more precise than it is.

Does my Practice data leave my browser?

No. Rifle profiles and practice sessions on the Practice page are stored only in your browser's local storage. Nothing is sent to a server. You can export a JSON backup or delete everything at any time from that page.

Does Within Range work without phone signal?

Yes, once you've loaded it at least once with a signal. Your browser keeps a copy of the calculator, DOPE table, and other pages, so they keep working with no signal, including in the backcountry. Content updates the next time you have signal again. Your saved practice data is unaffected either way, since it never left your browser.

What does "binding" mean in the result?

The calculator walks outward from 25 m and finds the first range where each of two limits is crossed: the precision limit (placement confidence falls below your target) and the energy limit (impact energy falls below the species' context reference). The nearer of the two is reported as the binding range, with the reason stated.

Something looks wrong with a number. What do I do?

Check the assumptions panel first. It lists every input and source used for that calculation. If a source or figure looks incorrect, that is useful information: this project is still in its Phase 1 validation stage and relies on exactly that kind of correction.