Simple way to reduce runout

[fgregorio]

Sometimes its the obvious that I overlook.

I just stumbled upon this procedure.

When I set up a die on the press, if I tighten the lock ring with the press ram/ shell holder putting pressure against the bottom of the die, I get close to zero runout. Works great on Lee Collet dies and redding competition seating dies. Actually it works great on any die.
With the LCD I tried either using an empty case as the gauge. Empty shellholder against the bottom of the die sleeve seema to work marginally better.