Smokepole,
The disadvantage of a bushing die is that it forces a donut on the INSIDE of the neck. Also, if your brass is fired in a generous chamber, as most SAAMI chambers are, there is NO advantage to using bushings, as the case is still reduced then expanded in the chamber again.
Also, an expander will make a neck rounder than a bushing, simple physics.
A bushing die that partial FL sizes each time will work the brass less because after a certain number of firings with neck sizing, you will have to push the shoulder and case body back to get it to chamber again, even an unsized body is being worked everytime it is fired from springback.
It is quite possible to size a case just under the springback dimension allowing a slightly loose fit, what I do, and still get lots of firings on each piece of brass. I have never found a neck sized case to be more accurate or last longer than a minimally sized case that is just short of chamber spec. Hard bolt closure will result in crooked cartridges, whereas a slightly loose case will self centre as the bullet reaches resistance on the lands.
Cheers.
Not quite. I agree on the expanding to the chamber part, but there's the other direction of brass movement to consider. For example, a standard 308 Win size die will reduce the OD of the case neck to .330", or even a little smaller. This is fine with thin WW brass which winds up with a loaded OD of about .332" or .333". However Lapua brass, brass from Federal match ammo, and a lot of LC, WCC or other "NATO" type brass winds up with a .338" loaded neck. So the sized neck OD for those ought to be about .335". It follows that with a conventional die the latter types of brass wind up getting an extra bunch of cold working: the excess .005" down to .330" and then .005" in the other direction when the expander brings it back up to the ready to load .335".
By proper selection of bushings, or by use of the Lee collet die, the excess cold working in the sizing down direction can be eliminated.
My preferred sizing method is a Lee collet die paired with a body die, or a Forster FL die with its neck honed to suit the thickness of brass I'm using.