I can tell you for certain that if I run a 5 piece of Winchester (any cal.) through a flare die or a seat/crimp die and then you sneak a piece of R-P in there on me, I will feel the difference. And if I can feel it in a press lever, I know it's constructed "differently" enough that it bothers me.
This is a key point for me. I am not a salty veteran but I can feel
the difference between cartridges when I make them. Even though I know at 25' it wont make a difference, for each box of 50 handgun rounds I load, I sort by headstamp and then while loading, I further sort by "feel". Those that are the "correct" feel go in the boxes unmarked, those that have a "different" feel go in the same boxes with a dryerase marker slash or X on them. I use the marked cases for barrel fouling or similar purposes.