Truing to your dope

The model predicts; your firearm decides. Truing corrects the model to match what you actually observed: enter a range you shot and the elevation dial that centered your group, and the solver inverts itself to find the input that matches.

Which input gets corrected

Which input gets corrected follows where you shot:

• Inside the supersonic range, trajectory error is dominated by muzzle velocity — true the MV.
• In the transonic zone and beyond, drag-model error dominates — true the drag scale.

The sheet computes the Mach number at your range and pre-selects the honest choice, and tells you why.

Applying and saving

• Use in this table applies the correction to the open calculation only.
• Save to ammo stores it with provenance (“Trued at 850 m, 2026-07-06” in the ammo’s note), recording the firearm it was trued in — truing is always an explicit act, never silent.

One caveat, on purpose: your measured chronograph mean always wins over a trued muzzle velocity, so if a load already has measured strings, correct its drop by truing the drag instead.

When it can’t be matched

If the dial you enter can’t be matched by any plausible value, the solver says so instead of forcing a fit. Check the range, the dial, and your zero.