dies neck or full length

[Rocky Raab]

You can't nexk-size forever. Sooner or later (usually sooner) you have to full-length size or the case simply can't be re-chambered.

Cases grow a bit with every firing, both in headspace length and in diameter. Because no chamber is perfectly round or symmetrical, and also because the case never goes in with exactly the same orientation, that means it soon becomes impossible to chamber.

Personally, I have never neck sized at all. I do partially size some cases using the FL die (backed off a quarter turn or so from full down) to get a slightly "fuller" chamber fit. That works well for me and I never have to change the setting.