An app by JS IT ApS
Internal ballistics for precision handloaders.
TRT (Target Reloading Tool) models your load from the inside out — calibrated powder data, charge-ladder simulation, and optimal barrel-time analysis — so you can develop accurate, repeatable loads with confidence. For iPhone, iPad, and Mac.
Coming soon to the App Store How it works →
1 mile with a 6.5 Creedmoor Tikka Tac-A1 in beautiful UK.
Calibrated load data
Powder parameters fitted to published manufacturer data across multiple cartridges and powders, kept current through the app.
Charge-ladder modeling
Simulate velocity and pressure across a charge range, with clear flags when a load becomes compressed.
Optimal barrel time
Barrel-time analysis to help you find the accuracy nodes that matter for your rifle and components.
Built for the field
Your data works fully offline at the range — no signal required once it's on your device.
Garmin Xero C1 & C2
Capture muzzle velocity straight from your Garmin Xero chronograph over Bluetooth — live as you fire on the C2, or synced from the C1 — flowing directly into your load and the barrel-time analysis, with no manual entry.
Recoil-timed shots
A rifle-mounted recoil sensor (Bluetooth) times every shot and logs it automatically against the load — building shot-by-shot data for OBT confirmation, with no stopwatch.
ShotMarker group analysis
Capture your shot groups live from a ShotMarker electronic target over Wi-Fi — group size, mean radius, point of impact and vertical dispersion logged automatically against each load, so you can line up accuracy with your velocity and OBT nodes on one confirmation chart.
In the works
What we're building next — closing the loop from load development on screen to confirmed, automatically captured data at the range.
Planned
Calypso ultrasonic wind meter
Live wind speed and direction from a Calypso ultrasonic wind meter over Bluetooth — measured wind straight into TRT, so your wind call is read, not guessed.
Planned
FX True Ballistic Chronograph
Direct, wireless velocity capture from FX Airguns' True Ballistic Chronograph radar — every shot straight into TRT, no manual entry.
Planned
Athlon Velocity radar
The same direct, wireless velocity capture from Athlon's Velocity radar chronograph — your data, straight into TRT.
Garmin and Xero are trademarks of Garmin Ltd.; Athlon and Velocity are trademarks of Athlon Optics; FX and FX Airguns are trademarks of FX Airguns AB; Calypso is a trademark of Calypso Instruments; ShotMarker is a trademark of its respective owner. TRT is an independent product and is not affiliated with, endorsed by, or sponsored by Garmin, Athlon, FX Airguns, Calypso, or ShotMarker. Device and product names are used only to describe compatibility.
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.
About
TRT is developed and published by JS IT ApS, a Danish software company. We build focused, dependable tools for people who care about precision.