603Country, One of the main reason for using bushing die here it is from Redding site.
A decapping pin retainer is also supplied with most Type S - Bushing Dies except 17 and 20 Cal. This enables neck sizing without the use of the size button for those who sort and/or turn case necks for uniformity.
You may or may not see any improvement in accuracy adjusting neck tension in a factory chamber but you may want to try that also.
What I do on all my new cases is use Sinclair expander mandrel in whatever cal I'm loading then use bushing die set neck tension. I also mike neck thickness after few firing that can change effect bushing size also.
Always fun to try things