Print at exact scale
The sheet includes a calibration bar and a fresh target ID. Print at 100 percent with scaling turned off.
Measure the group.
Photograph a paper target. Tackdriver measures the group, calculates optic clicks, and stores rifle and pistol zeros with each gun.
Free on iPhone. Works offline. No ads, subscription, or account required to start.
From paper to a working zero.
Print the sheet, shoot it, and scan the whole page. Tackdriver recovers its physical scale before measuring the holes.
Scan and check the holes
Corner markers correct perspective. Review every detected hole, move an uncertain mark, or add one the camera missed.
Turn the right clicks
Tackdriver uses the gun's MOA or MRAD optic and your chosen zero distance to calculate elevation and windage corrections.
Print the target you need.
Rifle zero, pistol zero, diagnostics, group tests, load ladders, and drill sheets print at exact scale from the app.
Every print gets a new target ID, tying the scan to the paper you actually shot without reusing an old record.
Know the course before the timer starts.
Every drill names the target, distance, round count, strings, par, scoring rule, and exactly how to run it.
Timed stages include a three-second ready countdown and keep each string in order from first shot to final scan.
Measure the zero before you trust the solver.
The target, rifle, load, atmosphere, and trajectory stay in one range record. Weak evidence gets a warning, not false precision.
- Group confidence
- Bounds show what the sample can support.
- Trajectory engine
- Three-degree-of-freedom point mass with RK4 integration.
- Long-range effects
- Spin drift, aerodynamic jump, Coriolis, and inclined shots.
- Velocity truing
- Back-solve muzzle velocity from measured drop.
Checked against published trajectories to 1,000 yards.
Continuous tests compare velocity, time of flight, drop, and wind drift. Drag functions include G1 through G8 and RA4.
The range still works when the signal does not.
Measurement, printing, ballistics, and the logbook work offline. Private records stay on your phone and can sync through your private iCloud database.
Read the privacy policyThe first questions
How does Tackdriver measure a rifle group from a photo?
Printed corner markers let the app correct perspective and recover the target's physical scale. It then measures the holes in the target's own coordinate system.
Does it work without cell service?
Yes. Target printing, scanning, group measurement, ballistics, and the local range logbook work offline. iCloud sync and public features wait for a connection.
Can it tell me how many scope clicks to turn?
Yes. Add the optic's adjustment value and direction, then Tackdriver converts measured point-of-impact offset into the correct number of clicks.
Can I choose a different rifle or pistol zero distance?
Yes. Rifle and pistol zero distances are adjustable, and corrections use the selected firearm and its MOA or MRAD optic settings.
Do the drills include targets and a timer?
Yes. Every drill includes a printable target and complete course of fire. Timed stages add a ready countdown and per-string timer.
Is Tackdriver free?
Yes. Tackdriver has no subscription, no advertising, and no paywalled features.
Does Tackdriver upload full-resolution target photos?
Private scans stay in the private logbook and private iCloud database when sync is available. A public post includes a smaller copy only when you choose to share it.
Bring paper. Bring your phone.
Tackdriver for iPhone is free, offline-first, and preparing for App Store release.