Offline

Range validation

Chronograph Sample Planner

Estimate how many shots to record, how much buffer you have over the PF floor, and what confidence band that delivers.

Projectile weight used with expected velocity to estimate power factor.

Used for power factor math.

Best estimate of this load's true average velocity, ideally from a previous representative string.

Your last string average or chrono target.

Official minimum power factor for the applicable scoring division. Confirm current rules before a match.

125 for USPSA/IDPA Minor, 165 for Major.

Expected standard deviation of individual velocities. Use a prior string from the same load and conditions; higher SD requires more shots.
Desired confidence-interval half-width around the estimated average. A smaller margin requires a larger sample.

Half-width of the confidence interval you want.

How often intervals calculated this way should contain the true mean across repeated representative samples. Higher confidence requires more shots.
Shots fired before recording the statistical string so the firearm and bore reach representative condition.

Excluded from the statistical count.