In theory, yes but it's becoming an antiquated process and not really necessary. I neck sized only for several years for a couple of my higher end rifles and they shot well but you do pay somewhat of a price with regard to how smooth your action is in the field and potentially your feeding reliability. I recall reading somewhere that neck sizing only can also be hard on the bolt face and the bolt lug mortises but not sure about that.does neck sizing only on brass fired in ones rifle improve accuracy by making the loaded shell square in chamber (concentricity). looking for consistency.
Agreed about the concentricity gauge, and in fact that particular tool is high on my "I want one of those" list. .Imo neck sizing is more about preserving your brass by reducing case hardening & not working the whole case.
In saying that you still need to anneal.
The amount of 'runout' produced in any sizing process using comes down to the quality of the dies.
A lot(probably most) BR shooters remove the expander from even their top quality dies & use a specific sized mandrel to give a specific amount of neck tension but also to improve concentricity.
I would also say neck turning would also assist in this, which is why they(BR shooters) do both processes.
Using the mandrel in place of the dies rod improves alignment.
Still, you really need to get yourself a concentricity gauge to measure all this otherwise there is no point.
Very interesting take on the situation from someone who should know. Thanks for sharing that!Click on image to enlarge