BC Calibrator

Fits your projectile’s ballistic coefficient to reality, using the shots you have logged with measured drop. Where the Truing Table shows you the error, the calibrator removes it.

It opens on data you already have, so it is reached from that data rather than from the drawer: the Calibrate button below the Truing Table widget, or the same button at the foot of a session in the session editor. Either way it needs an active profile and location, plus logged shots carrying measured drop (see Sessions & Logging).

On the web the calibrator is part of the Cloud-Sync subscription; the mobile app includes it.

Modes

• Scalar: scales the whole BC by a single multiplier. The simplest, most robust fit; start here.
• Segmented: tunes each existing BC velocity band separately. Needs a profile whose projectile already has two or more bands, with data in more than one.
• Propose: derives new velocity bands from your data and fits an independent BC per band. Needs at least 4 shots across a range of velocities.

Flow

1. Pick a mode and tap Calibrate.
2. Review the fit: Current vs Fitted BC, the Multiplier, and the RMS error, plus a Drop Comparison table and chart of current vs fitted predictions against your reference shots.
3. Apply it:
   • Apply to Profile: updates the active profile in place.
   • Save as Variant: saves a calibrated copy of the projectile to My Projectiles, leaving the original alone.

Notes

• Garbage in, garbage out: velocity errors masquerade as BC errors. Chrono the load and true the muzzle velocity before truing BC.