Concentricity and Urban Myths

[jasper2408]

For years conventional wisdom has been that “pulling an expander ball” up through the neck of a case caused concentricity issues. That is, the case was weaker in tension than in compression and we all happily stumbled along in agreement. People pulled the expander ball assembly out of their resizing dies and added a neck resizing expander mandrel to their brass prep regime. An audible hush fell over the crowd! Life was good!

Enter SAC, (Short Action Custom) and their tapered bushings.

https://youtu.be/D2Gei8Wo6UA

And

https://youtu.be/KqB4wrHO7fQ

Maybe it’s not quite as simple as we first thought?

Anyway, it’s been almost a year now and they, (SAC bushings), have cut my concentricity issues down to almost non-existent. And that’s with re-employing an expander ball to the resizing operation. No more mandrel, or associated extra step.

Lube, resize with SAC bushing and expander ball (I use the Whidden expander ball system because the diameter is adjustable). Done! Just the like the old days but, with almost no runout!

Happy 4th of July Folks!

Are you still using PEG-75 lanolin to lube your cases?