I think every seating die is designed wrong. Here's why.

[Rat Rifle]

I don’t see any reason to have “severe“ run out, so given that yes, when the bullet leaves the barrel, if it’s not straight by that time, it never will be. JMO

edit…I guess everyone wants instant gratification. Assuming I am seating into a straight neck, I can take a LEE seating die, seat 1/16”, rotate the case, seat another 1/16”, repeating until final seat, providing practically zero run out. I have time for this, but probably most don’t.

 

[Dusty Stevens]

Once a bullet engages the rifling crooked it is formed and pressed into the barrel crooked and will never straighten out. It is swaged into that shape