Range data & statistics

Log a string of chronograph shots against a load or ammo — typed, pasted (decimal commas fine), or imported from a chronograph CSV (ShotView, LabRadar, Garmin Xero, generic; m/s columns convert automatically).

Raw shots are immutable

You can flag a shot (called flyer, cold bore, clean bore, excluded) and flags change what the statistics include — but the measured number itself is never edited or deleted. Your data is your data.

Honest statistics for small samples

The statistics are deliberately honest for small samples: means and standard deviations come with confidence intervals, and those intervals are wide when you’ve only shot five rounds — because with five rounds you genuinely don’t know your SD tightly.

An SD of “8.2” from a 5-shot string is a guess dressed as a number; the interval is the truth. Extreme spread (ES) is shown because shooters use it, but SD with its interval is the better tool.

Drift and compare

• Drift checks whether velocity trends over the string (barrel heating, fouling).
• Compare runs a proper two-sample comparison (Welch’s t for means, bootstrap for SDs) — “the means differ” only when the data actually supports it.