Re: Fixing bullet runout?
The answer to your question is simple as all get out: Lee collet neck die and a quality seater such as the Redding Comp or Forster Ultra.
By design the Lee collet neck die does not have an expander, so one potential problem is eliminated there. It sizes the neck against a mandrel from the inside rather than the outside like other dies, so another source of runout, case thickness variations, is eliminated. It requires no case lube, a very nice convenience IMO. I now use the Lee collet neck die for every cartridge I reload for and have eliminated excess runout as a source of any accuracy problems I might be having.