Zima: Ballistics Calculator icon Zima: Ballistics Calculator
How-to

Quick answers, step by step.

The questions shooters ask us most, each answered in a few steps on the same screens you will see in the app. Works the same on iPhone and Android.

Getting started

Add your rifle and get your first firing solution Add your rifle in the Armory with the five-step guided setup, put it on the bench, then enter your range, weather and wind on the Calculate tab and tap Calculate. The Drop Table then gives the hold for each range.

Zeroing

Zero a different load without burning a box of ammo Add the new ammo as a second load on the same rifle and tell the app which load you zeroed with. It estimates where the new load hits from the two loads’ speeds, bullet weights and drag, with no shooting, and three shots at the range make that estimate exact. True your drop with real data Set the Calculator to the day's weather, shoot at a range well past your zero, and enter the range and the measured drop in Truing / Calibration. It returns a trued muzzle velocity or BC, which you then type into your load. Find the best zero distance for your load There is no single best zero for a cartridge, because it depends on your load, your sight height, the air and the distances you shoot. The Zero Distance Explorer's Find Best Zero tries every whole yard or meter for your load and lists the three zeros that keep the bullet closest to your point of aim across the range band you set.

Wind

Enter the wind and read the wind hold On the Calculate tab, type the wind's speed and the direction it comes from on the Wind card, then tap Calculate. The wind hold is in the Wind column of the Drop Table and in the Corrections & Reticle tab, with an arrow that points into the wind.

Reticles and units

Switch between MIL and MOA and set your click value Switch the unit your holds are shown in with the MOA, MIL and IPHY switch above the Drop Table, or under Settings, System, Angular Unit. Then set what one click is worth on your optic's own page, Edit Optic, with its turret switch and Click Value. Hold on your reticle's marks for a shot Put your reticle on your optic, open the Reticle Simulator with your rifle, set the range and wind, and turn on Show Hold Overlay: a red dot marks the point on your reticle to put on the target, with the numbers beside it. Turn on Show Trajectory Trace and each mark is tagged with the range at which the bullet reaches it.

Your rifle and loads

Enter your muzzle velocity and correct it for temperature Type the average speed from your chronograph into the load's Muzzle velocity box, then set Reference temp to the temperature you measured it at and Temp sensitivity to how much your powder's speed changes per degree. If you do not know the sensitivity, Work It Out From Two Readings figures it from two chronograph averages taken on days with different temperatures. Choose the right BC and drag model for your bullet Pick your bullet from the Bullet Database or the load's Choose Bullet list, and the app fills in the maker's BC together with the drag model that BC was published for. If your bullet is not listed, type the BC from the box or the maker's website and set Drag Model to the model the maker states it for, because a BC only works on the drag model it was measured against. Check a subsonic or short-barrel load Yes, the Calculator solves whatever muzzle velocity you type, and its Warnings list says the bullet is subsonic from the muzzle when the load leaves the barrel below Mach 0.8. Effective Range and Ethical Shot Distance show No range, with the reason in numbers, when no range they check passes the limits you set.

Conditions and devices

Use a Kestrel for your conditions Connect the Kestrel in Bluetooth Devices, then touch and hold the weather button on the Calculate tab, choose Kestrel Live, and tap Apply to Calculator. The meter's temperature, pressure, humidity, altitude and wind speed go into the Calculator, and the Atmosphere card names the Kestrel as the source.

Sharing and backup

Send a load or a rifle to a friend In My Armory, touch and hold the load's card and tap Share to send it as a small file, or touch and hold a rifle and tap Share Rifle to send it with its loads and zero as a file, a link or a QR code. Your friend opens it in Ballistics Calculator on an iPhone or an Android phone, checks the preview, and adds it. Back up your data and move to a new phone On an iPhone, your rifles, loads and logs back up to your own iCloud Drive, and a new iPhone signed into the same Apple ID offers Restore from iCloud the first time the app opens. On Android, save a backup to a file or cloud drive with Backup to Cloud / File in Settings, then use Restore from Cloud / File on the new phone.

Hunting

Check your load's energy and speed at range for game The app does not decide how far is right for you: it shows your load's energy and speed at a range, and works out where the limits you set run out. Use Terminal Ballistics or Effective Range for the facts at a range, and Ethical Shot Distance to see which of your own limits ends first.

Where to look

  • How do I do this? You are in the right place. Short answers, one question each.
  • What does this button do? The Operator’s Guide describes every screen and control, with pictures.
  • Why does it work this way? The Training Academy inside the app teaches the ideas behind the numbers with lessons and drills: wind, zeroing, MIL and MOA, reading a reticle and more.
  • Something not right? Contact support. A question we get twice becomes an answer here.