Verify everything that should not move
Confirm target distance, zero, units, sight geometry, drag model, and environmental conditions before changing velocity or BC.
Protect a trustworthy chronograph value
When muzzle velocity comes from reliable chronograph data for the current ammunition and conditions, prefer investigating or truing drag behavior before rewriting velocity from drop.
Question velocity only with evidence
Consider velocity truing when chronograph data is absent, suspect, or clearly inconsistent with repeatable observations after the other inputs are verified.
Change one model input at a time
Record the observation, apply one correction, recalculate, and compare the entire useful curve. Simultaneous MV and BC changes can hide which assumption was wrong.
Re-validate at other distances
A trued value is a proposal until it improves agreement across more than the calibration distance.
Expected result
The adjusted profile has a recorded reason, preserves trustworthy measurements, and improves agreement across multiple distances without unexplained side effects.