Re: age old question....neck size or full length size?
It's a little more complicated as far as I see it.
My Comp guns get both, that's the idea behind a bushing die, partially resize the neck to help align the case in the chamber. It also full length sizes the case to ensure that it feeds into the chamber and the bolt closes. I only bump the shoulder .001" to .0015" it's the dies job to minimal resize the rest of the case. In some instances I have custom made busing dies made specifically from the dimensions of the chamber reamer which has even closer tolerances. The last thing you want is a case that won't load into the chamber during a record string. I use my comp guns for long range hunting so it applies for both. My Varmint guns are a bit different, I neck size just like Bob the Blacksmith, when they start to close hard I bump the shoulder with a bump die. I'm not too concerned if a ground hog gets a second chance because of feeding problems, more times than not when it does happen he's far enough away I have plenty of time to grab another shell.