Nice article on neck tension. Grip on Bullet ? Many Factors Involved, Not Just Bushing Size « Daily Bulletin
As a former competitive bench rest shooter, I ain't touching this subject with a 11 foot pole.
And whatever you do - DON'T go out and test anything yourself by actually shooting your gun and looking at the results. Just sit on your azz and listen to theories on the internet - then go buy stuff based on that.
Next up: Do I need to lap my rings, chapter 3.0