TrueData – Ballistic Calculator

What is TrueData?

TrueData is a free Android tool developed by Sierra Bullets that helps shooters calculate ballistic solutions on the go. By entering the details of your rifle, bullet and current weather conditions, the app provides real‑time click adjustments, trajectory tables and wind‑drift estimates.

Main features

• Comprehensive ammunition libraries – Includes the full Sierra and Barnes bullet catalogs as well as Doppler data for both manufacturers.
• Custom rifle and bullet profiles – Create, edit and save multiple rifles and bullet entries, each with its own muzzle velocity, ballistic coefficient and other parameters.
• Dynamic click calculations – Instantly see how many MRAD or MOA clicks are needed for a given distance, wind speed and direction.
• Multiple weather inputs – Use the device’s location to fetch current weather, or manually override temperature, humidity, pressure and altitude.
• Support for various drag models – Choose between G1, G7 and other drag functions to match the bullet you are using.
• Trajectory tables and reports – Generate detailed tables that show zero range, transonic zone and drop at any distance; export options include CSV, TSV, pipe‑delimited text and PDF.
• Wind and spin‑drift handling – Fine‑tune wind direction, speed and spin drift for more accurate aiming.
• Convenient tools – Includes a training timer, quick compass for wind cards and haptic feedback for button presses.

How it works

After launching the app, you start by selecting or creating a rifle profile. Enter the barrel length, twist rate and any zero offset you use. Next, choose a bullet from the built‑in Sierra or Barnes libraries, or add a custom entry with its ballistic coefficient and muzzle velocity. The app then asks for weather data; you can let it pull the current conditions automatically or type in your own values.

With these inputs, TrueData calculates the required turret clicks for the distance you specify. You can switch between metric and imperial units, and between MRAD and MOA click values. The main screen shows a concise summary, while a deeper view provides a full trajectory table and a visual representation of wind drift.

Practical uses

• Long‑range target shooting – Quickly determine the exact number of clicks to adjust for wind and elevation.
• Hunting – Estimate bullet drop and drift for various distances to place shots more confidently.
• Training – Use the built‑in timer and target cards to practice shot timing and data recording.
• Field work – Connect a compatible Bluetooth weather sensor (such as Skywatch or WeatherFlow) for live updates while you’re on location.

Installation information

TrueData is available as a free download from the Google Play Store. The package name is com.sierraballistics.truedata. No purchase is required, and the app does not contain in‑app advertisements.

Things to know before installing

• The app works offline once you have entered your data, though weather fetching requires an internet connection.
• It supports both metric and imperial measurement systems, allowing you to choose the units you prefer.
• Data such as rifle profiles, bullet entries and custom settings can be exported and imported via common file formats, making it easy to back up or share configurations.

Who may find it useful?

Anyone who regularly shoots at extended ranges – competitive shooters, hunters, military or law‑enforcement marksmen – will benefit from the precise calculations and flexible data management that TrueData offers.

Frequently asked questions

Do I need an internet connection?

Only for fetching live weather data. All ballistic calculations run locally on the device.

Can I use my own bullet data?

Yes. The app lets you add custom bullets with specific ballistic coefficients, muzzle velocities and drag models.

Is there a limit to how many rifles I can store?

No. You can create as many rifle profiles as you need, each with its own zero and elevation settings.