This question is the result of something I read on another forum,
here.
In the 5th post down, someone makes the following comment, and being an inquisitive Newbie, I am trying to understand the implications.
"Note on compressed loads if that's what you choose:
Make 2 or 3 at whatever OAL you specify, measure carefully
with the caliper or micrometer and write it in Sharpie on the brass itself.
Let them sit overnight, then measure the next day and write that number.
Increasing OAL means you have compressed too far.
If no change in OAL or it grows only a tiny bit (.010 or .015 inch)
and then stabilizes, you're good to go."