Mike ,
Some people claim they have turned case necks that were way out and got no improvement , others swear by neck turning . The neck expands when the round is fired and the thicker part of the neck presses against the side of the chamber before the thin side so ? . Turning the neck surely couldn't hurt . I'm seeing more and more the reasons to use high-end brass if consistent small groups are something you need for that rifle.
No on the LCD it presses the neck around a mandrel - if brass has thick spot in neck it'll still be thick after running it through a LCD .
