On revolver rounds, typically with purchased lead bullets, if a cartridge will not pass the gauge, recrimping often works, else I try the FCD with the stem removed. If that doesn't work, I pull the bullet. If it happens on more than one or a few, I reset the crimp die and seating depth after a good cleaning. I don't usually feel much resistance through the FCD sizing ring, so to say the bullet gets swaged or the neck tension is disturbed seems too melodramatic, a lack of objectivity.