Originally Posted by
truckjohn
There's an old practice of only screwing a full length sizing die down till it produces an acceptable length cartridge for your rifle.
If you read the press and die instructions, they say not to do this, though. They want the die to barely kiss the shellholder when the press closes all the way.
Why?
Slop in the press joints. It can cause presses to "Squish" the case a little different with each stroke if you aren't touching the shellholder. This leaves very inconsistently sized cases. 0.010" doesn't sound like much, but it may as well be a mile too long when it sticks in your chamber.
The issue with trying to avoid over working your brass is that each rifle is a little different, and some have longer chambers than others. In this case, Redding makes a set of shell holders that allows something like 0-0.020" additional depth for setting up cartridges for individual rifles. This way, you can still operate the FL die correctly, yet only size the minimum for your gun. So handy.