Re: Neck Turning
I neck turn everything. It's because I use Redding Competition dies for everything. The turned necks allow you to use their neck bushings which size the outside of the case neck without an expander ball inside. Less work on the brass, and consistant neck tension. The dies are also awesome at doing away with neck and bullet runout if you set them up properly. You see, the neck turning is not an ends unto itself, it's a way of accomplishing other goals. If you're using dies with an expander ball, you won't gain very much... your neck tension is already pretty consistant because the imperfections of neck wall thickness are forced to the outside by the ball. The bushing dies force the imperfections to the inside where they have a more drastic effect on the neck tension.
You can check for concentricity with a number of tools. I use the RCBS Casemaster. You can check cases for concentricity, neck runout, casehead separation, neck thickness and bullet runout with this tool.
If you're trying to turn a 2" group into a 1" group at 100y then most of this isn't necessary. If your trying to turn a 1" group into a 1/4" group then by all means... start throwing $ at the sport and have fun!!!
All it takes is One Good Shot!