Originally Posted by BountyHunter
Not true at all.
Take the KM arbor press with the dial indicator on top and inline die and you can see, measure and feel the difference. No dial indicator and you can certainly feel the difference when seating. That is routinely used for neck turned brass for 1k BR shooters to sort rounds as loading for "match" or "sighter" category.
IME there is a definite increase in seating pressure when going from one bushing size to another in a bushing neck sizer and also when using different size mandrels that I ordered from Lee for the Lee Collet neck sizer. IOW, by changing the bullet grip. By contrast when I have sized cases with the Lee Collet for a factory rifle on cases that I have not neck turned, I can get consistant seating force even though there are neck thickness variances. However the Lee Collet mandrel I normally use for factory rifles gives only .001" bullet grip so that may have some bearing on the seating force.
Differences in seating force IME (after standardizing the ID) has been much more dependent upon the condition of the inside of the neck. On mine I use no lube, scour the inside with scotchbrite, smooth the inside with steel wool and then use mica
in order to make for as consistant seating force as possible.
So I get consistant seating force with cases I have not neck turned and I get consistant seating force with cases that I have neck turned. IME the seating force changes noticeably with changes in bullet grip.