After experiencing increased neck runout using a full length Redding resizing die with carbide expander ball, I have decided I need to iron out dents and expand the neck using a mandrel tool. Neck runout without the expander is about .001", (about the same as neck thickness variation) but with carbide expander jumps to about .004". I presume the mandrel is used after a full length resizing (this is for an AR15) and then expanded using the mandrel. I welcome guidance on how to use, as well as whether the K&M or Sinclairs is a better bet. The Sinclair mandrel floats on an O-ring so it can center in the case neck. I do not think the K&M does. Reloading press is a Forster Co-Ax.
Thanks.
- Phil
Thanks.
- Phil