[wncchester]

"The most important thing for getting increased accuracy is having cases that have been fire-formed in you chamber so they have minimum head-space."

Well, that's not quite correct as stated. The most critical thing in an accurate handload is finding a bullet that will shoot well. Next is proper selection of powder and charge, then finding the optimum OAL/seating depth. Everything after that is a tweek for minor gains.

Truth is, in the search of accuracy there are no absolute steps that if you do this or do that you will have better results but it sometimes seems that way to mid-level reloaders. There are many things involved in obtaining accuracy and neck sizing, per se, is perhaps one of the least predictable. But, when it does help, the Lee Collet is perhaps the best available for neck die for factory rifles.

Methods such as inside neck reaming does nothing for accuracy, it just thins the necks. Outside neck turning in loose chambered factory rifles rarely does much good. Other oft mentioned ideas as trimming all cases to identical length, seating on the lands and measuring seating off the ogive, having high "neck tension" (actually an accuracy killer), precision weighing of powder charges or bullets or cases, or buying some magic brand of bullets or powder or primers or cases, or using specific brands of tools are common accuracy myths.

The value of such things as flash hole deburring or primer pocket uniforming depends on how bad the flash holes and pockets were. If they were good, or even close to good, it certainly won't make much difference. But if they aren't so good the improvement can easily be seen on target. Even then it's only a tweek and won't reduce 1 MOA groups to .25!

Neck sizing may help extend case life but even that's not a certainty. Most case stretch occurs because of excessive FL sizing, jamming the cases as far into the size die as they can possibly go. Even so, few necks will last long enough for bullet pinch to occur in factory chambers. FL sized properly, cases will die from neck splits (or head seperations) long before bullet pinching occurs.

Skunk, I've typed all this for you. Understand that knowledge and skill (or pure luck!) are the keys to finding an accurate load and that doesn't come fast. What works in one rifle, or one type of rifle such as Bench Rest vs. factory sporters, rarely crosses over so there are no universal methods or "pet loads" that can be assured of any kind of result on target. Try everything because ONLY experimentation and testing can confirm anything for any given rifle.