Precision Ballistics Solver

Shoot the math.
Trust the dope.

Trajex is a precision exterior-ballistics calculator for rifle shooters and handloaders. Two real solvers, a 1,279-bullet database, live atmospherics, Coriolis and spin drift — on the iPhone in your range bag.

« Built for handloaders who measure twice and shoot once. »
Free No ads No login Local-first
Trajex app icon: a glowing amber parabolic trajectory arc bisected by a white crosshair on a dark textured background.
What's inside

A field instrument, not a toy.

Every feature earns its place. No ads. No subscriptions. No telemetry.

01 Two Trajectory Engines

MPM & full 6-DoF

Modified Point-Mass and a full 6-Degree-of-Freedom rigid-body solver. Choose per shot, or compare both on one chart.

02 1,279-Bullet Database

15 major manufacturers

Curated projectile library with G1 and G7 ballistic coefficients where the manufacturer publishes them.

03 Live Atmosphere

One-tap GPS & weather

Pulls pressure, temperature, humidity and wind from Open-Meteo at your location. Or enter every field by hand.

04 Coriolis & Spin Drift

Computed automatically

From latitude, firing azimuth and bullet spin — no toggles to forget, no separate calculator to consult.

05 Scope & Reticle View

True MOA / MIL graduation

Shows holdover and wind hold for the target distance on a graduated reticle that matches your optic.

06 Rifles & Loads

Recipes, not duplicates

Loads are rifle-independent recipes linked by cartridge. One load, every rifle chambered for it.

07 C.I.P. Cartridge Catalog

405 cartridges, 401 TDCC sheets

Official C.I.P. dimensional reference for case, chamber and headspace — built in, always at hand.

08 Local-First & Private

Your data, your device

Everything lives on your iPhone. Merge-only backup and restore — your records are never silently deleted.

The Differentiator

Two solvers. One chart.
Pick the right physics for the shot.

Most apps give you a single black box. Trajex gives you two named, distinct integrators and lets you overlay them. See where simplification ends and full rigid-body behaviour begins.

Engine 01 FAST

Modified Point-Mass

Industry-standard MPM integrator with drag, atmosphere, gravity, Coriolis and spin drift. Tuned for speed — perfect for quick range cards and what-if comparisons in the field.

Drag model
G1 / G7
Best for
Field solving
Engine 02 PRECISE

6-Degree-of-Freedom

Full rigid-body integrator: pitch, yaw, roll and translation in three dimensions. Resolves yaw of repose, gyroscopic precession and crosswind jump the way a flight simulator resolves an aircraft.

State vector
6-DoF rigid body
Best for
Load study, ELR
What you get

Every number that matters,
at every range step.

Drop, windage left and right, remaining velocity, energy and time of flight — computed for the full range band, not just your zero. Read it as a table, or scrub the interactive elevation and windage trajectory chart to find the transition that bites you.

Drop MOA · MIL · inch
Windage L / R per range
Remaining V fps · m/s
Energy ft·lb · joule
Time of flight seconds
Chart Elev · Wind overlay
Download

Bring the math to the line.

Trajex is on the App Store for iPhone. Free. No ads. No login. If it earns its keep in your range bag, leave a tip.

Free  ·  No ads  ·  No login