Exactly correct, Mike.

It actually takes pressures in the 40,000CUP range to stretch the case at the web, to re-seat the primer.
There may be some case slippage, especially with lubed chambers or brass, but the re-seating usually comes from stretching at the web.
When fireforming wildcats that need the shoulder moved forward a small amount, I lube the cases before firing.
If you are using factory loads for brass, then will be handloading them, it is a good idea to wipe the case with a thin lube, like WD40 prior
to firing for the firs time, so that there is no stretch at the web.
Your brass will last longer.