Guide

Truing: Fit the Model to Your Rifle, Not the Other Way Around

Every solver output is a prediction built on three things that are not quite your rifle: the factory's muzzle velocity (from their test barrel), the published BC (from the manufacturer's range), and standard air. Truing closes the gap with the only authority that outranks all three — your bullet holes.

The method

1. Chronograph if you can. A measured muzzle velocity removes the biggest unknown. No chronograph? Truing still works — it just loads all the error onto the velocity, which is honest enough inside the range you trued at.
2. Confirm your zero. Truing on a bad zero corrupts everything downstream. Shoot the zero distance on paper first.
3. Shoot a mid-range target — 500 to 700 yards is the sweet spot: far enough that velocity error shows clearly, close enough that BC error hasn't taken over. Measure the group's center against your point of aim, in inches or in scope units.
4. Enter the observed drop. The solver adjusts muzzle velocity until its predicted drop at that distance equals your measured drop. That velocity — usually 20–60 fps off the box number — is your trued MV.
5. Verify at a second distance. If the trued card matches at a longer range too, you're done. If it matches near but drifts off far, the BC is the remaining error — that's a BC true, done the same way at the longest range you can shoot well.

What truing is not

Truing fits a model to your measured impacts in your rifle. It says nothing about any other rifle, and it is never a source of load data — it adjusts the description of ammunition you already have. If your trued velocity is wildly off the expected figure (more than ~100 fps), stop and look for a setup error — scope tracking, zero, range distance — before believing it.

The TruingLog Kit stores the trued velocity against the load, so the corrected card is the one you print all season.