How it works

From a prediction on screen to your rifle's own model.

TRT has two sides. On one, you model a load and read what it should do — no gear required. On the other, you take it to the range, capture what it actually did, and let the app calibrate itself to your rifle. A chronograph is what joins the two.

A reloading tool — not a calculator for external ballistics. TRT works inside the barrel: charge, pressure, velocity, and barrel time. It does not calculate trajectory, bullet drop, or downrange come-ups — that's external ballistics, a job for a different app. TRT is not a calculator for external ballistics in any shape or form.

Made for Apple — and only Apple. TRT runs on iPhone, iPad, and Mac. That's the whole list — there's no Android or Google version, and there won't be one. If you'd like to use TRT, you'll need an Apple device. Sorry!

One workspace, all your devices. Your work syncs across your iPhone, iPad, and Mac. The sync is real-time — but that's not really the point. The point is continuity: set something down on one device and pick it straight back up on whichever one suits the moment.

Velocity data is the whole point. Be honest with yourself — without measured muzzle velocities, TRT has little to offer. An uncalibrated model is only a guess; real velocity is what turns it into your rifle's model. No chronograph yet? Our built-in simulator lets you see exactly what TRT can do with velocity data — so you can judge the value for yourself first. To quote from The Right Stuff: no bucks, no Buck Rogers. Here, it's no chrono, no clue.

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Two sides of the app

One works anywhere. The other comes alive at the range.

Calculate No hardware

Pick a cartridge, a powder and a projectile, dial a charge, and read the prediction: muzzle velocity, peak pressure as a share of the published maximum, powder burn, case fill, and the barrel-time (OBT) node you're closest to. Explore freely — this half works fully offline, with nothing connected.

Projects Needs a chronograph

Take the loads you want to test to the range, fire them, and capture the real velocities. TRT then calibrates the engine to your rifle so every later prediction is yours. This half only makes sense once real measurements flow in — and that starts with a chronograph.

The workflow, in order

The path the app is built around — the same one a careful handloader already follows.

Start in Calculate. Choose your cartridge, then the projectile for the job (hunting, match, distance). Read the predictions and find the charges worth testing.
Start a Project. A Project is one rifle + one cartridge + a goal. Add the loads you want to try — most people begin with a charge ladder, often across a few different powders.
Shoot the ladder and capture velocity. At the range, your chronograph feeds each shot's speed into the matching load.
Calibrate. One tap fits the engine's bore-fit to your measured velocities. From now on, Calculate predicts for your barrel — velocity and pressure both.
Read the nodes. Find the charge where barrel time lands on an OBT node, then confirm it with a group. That's your accuracy load.

Projects, series and loads

Your range work is organised in three simple levels.

ProjectThe goal

One rifle, one cartridge, one goal (e.g. “2,850 fps node, sub-½ MOA”). It holds your rifle profile — including the calibration you build up — so every session you shoot for that rifle lives in one place.

SeriesOne range session

The loads you fire together in a single session, all sharing one projectile. A Ladder sweeps the charge (≈1 shot each) to find the node; a Group fires a group per setting — e.g. a seating-depth test — to confirm precision. A chronograph's shots map onto the loads in firing order.

LoadOne recipe

A single powder / charge / seating. After the range it carries its own reality: measured velocities, group on target, and your pressure-sign call — and it's that measured data that calibrates the model.

The chronograph — the one piece you need

Everything else is a convenience. This is what turns TRT into your rifle's model.

The best fit today is the Garmin Xero C2. It's currently the only chronograph whose firmware broadcasts each shot in real time. Connect it in TRT and the app starts the session for you — no button-pressing on the device. As you fire your ladder, every shot streams straight onto the matching load, in firing order, and your rifle calibrates the moment you're done.

Chronograph	How data comes in	Live?
Garmin Xero C2	The app starts the session and streams each shot as you fire, mapped onto your loads.	Real‑time
Garmin Xero C1	Fire your string, then Sync over Bluetooth — TRT reads each shot from the saved data.	After the string
Any other chronograph	Export a CSV on the device, then import it into TRT.	After the string

Every chronograph works with TRT — only the Xero C2 does it live. All others publish their data after the string is finished, and you bring it in with a quick sync or import.

No chronograph yet? TRT ships with a Xero C2 simulator so you can see exactly how live, real-time capture feels — start a session, watch simulated shots land on your loads, and calibrate — all without any hardware. Try the Xero C2 emulator →

Beyond the chronograph: optional gear

Extra devices that refine your workflow — none of them required.

A chronograph is the one device you truly need. Beyond it, TRT connects to a range of other equipment — a recoil sensor that times every shot for barrel-time work, a ShotMarker electronic target that logs your groups live, and a Calypso ultrasonic wind meter (the Portable or the Mini) that reads the wind for you — with more integrations on the way. (Use a standard Calypso — not the Applied Ballistics (AB) version.) None of it is required; it's there to refine your workflow, not to gate it.

Want to try the integrations first? We've built emulators for the gear we support — but our emulators run on M5Stack Core2 microcontrollers: small, low-cost dev boards that are not included with TRT. To run the emulators, you'll need to buy one (or a few) separately. The chronograph is the exception — TRT's built-in Xero C2 simulator runs entirely in software, with no extra hardware.

The software, though, is on us. Every M5Stack program we make ships with TRT — flash it straight from our website in a Chrome browser on your computer, over USB, with no coding or toolchain. After that first flash, updates come over the air: TRT pushes new firmware to your M5Stack over Bluetooth, right from the app — no cable needed again.

Safety first

TRT is a tool to help you understand and develop loads — it is not a substitute for published load data or sound reloading practice. Always cross-check against current manufacturer data, work up loads carefully, and never exceed published maximums. You are responsible for the safety of every round you assemble.

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