Well sometimes is not what we're measuring, but how we're measuring it.

Runout or not you need a method to measure the same thing your shellholder saw sizing -seating, the longest point of any runout. If a piece of brass has .005" case head runout thats the point it will rest on sizing-seating. So, the most accurate and consistent way to measure it is the same way time after time.



The second bushing duplicates where the casehead contacted the shellholder during the sizing-seating operations including any variation around the primer pocket. It also ensures the case is always aligned consistently. The bushing is bored exactly .100"deep , so you can add .100" to the measurement for a real number if you want.

You might be surprised just how consistent your ammo is already.


Oh, to align the two bushing holders to be sure they're square....



Bill