Neck Sizing.........
of bottlenecked cartridges [.17Rem, .223Rem, .22-250, .30-06] is all I ever do, because.........
I recycle these cartridge cases back through the very same bolt action rifle each time they are reloaded. In that way they are custom fireformed to fit the very same chamber over and over. On some batches, I've used a Sharpie marking pen to dot-mark the "this-side-up" orientation, just in case the chamber was reamed at the factory on the Third Shift or by the New Guy. Most reloaders know that FL sizing works the brass; no point in doing so if not needed.
Neck sizing can be performed two ways:
1) Use FL Die, but only insert cartridge case partially, enough to size most of the neck, but not all of it. This method will usually not size the entire neck, because the tapered part of the case will soon meet up against the sizing die. And then you start FL sizing.
2) Break Down and Buy a Hornady Neck Sizing Die, which will.........only size the neck. Because it's made such way. You'll need one for each caliber you shoot/reload.
Most all reloaders know that FL sizing is needed when reloaded ammo may be used in different rifles of the same caliber. And maybe in .223 semi-autos w/fast firing.
And there's more to it, but that's enuf to answer your basic question.
