Runout and Reloading Dies   Knee-Jerk Reactions   Actual Causes   Resolutions   Conclusion  

Runout and Reloading Dies

Reloaders like to measure runout.

If you are one of them, then you have invested in equipment to check loaded round concentricity.

What you are measuring ? Is the runout you are seeing what you think it is ?

Break the concept down into it's componenets and think about them for a minute.

Runout is the measured deviation of the case neck axis from the case body axis.

When deviation is present, there are a limited number of factors able to cause it :

  • the decapping rod assembly
  • the seating stem
  • neck wall uniformity
  • brass hardness and springback

Factors that have nothing to do with runout are

  • the press
  • the sizing die body