FL resize VS neck sized?

full length resizes the whole case. neck size resizes just the part that holds the bullet. aka the neck.  only neck size if the case is used in the same gun. most likely it wont chamber in another gun of the same cal.  minimum case working = greater case life. bolt action bench rest shooters are the biggest proponents of neck sizing.

Thank You.

Well it's pretty straight forward. The part you probably really need to know is the why, not so much the what. There are pro's and con's for each method so I'll tell you what I know, and maybe some others can add to it.

Full sizing;
Returns the entire case back to it's original sammi specs. (Or it gets very close). This will be the closest you can get your brass to original un-shot condition.
Pro's - 1.)It should fit evey chamber for that caliber. In other words, a 22-250 case thats full sized should fit any 22-250 chamber. 2.) In an autoloader it can be important that the case is returned to 'new specs' because some autoloaders won't reliably load cases that have already been fired if they aren't full sized.
Con's - 1.) Everytime you full size the case it grows in length. You have to check the case length to ensure it hasn't grown to the point that it needs trimmed. If it's to long, it can hang up in a chamber when it hits the end of the chambers throat. 2.) Your brass may wear out a little faster because of all the expanding during firing, and then sqeezing it back down to 'normal' size.

Neck Sizing;
Just returns the neck back to standard size. Part of the purpose to sizing at all is to make the neck small enough to hold a bullet. In either full size or neck sizing the neck is sqeezed back down. Since you don't size the rest of the case you get different options and results.
Pro's - 1.) Some say (and I'm one of them) that neck sizing will give you better accuracy results. Because once the brass has been fired in your chamber, it fits that chamber nearly perfectly. This is because the case, and the bullet are at the closest they are ever going to be to the centerline of your bore, prior to firing. 2.)Your brass may last a bit longer, but honestly I haven't had any brass give up any sooner either way. 3.) You are less likley to need to trim your case length, but it's important to check it anyway.
Cons -1.) That piece of brass is probably only good for the chamber it was last fired in. In this case, your neck sized 22-250 may fit in your chamber, but it probably won't fit in your buddies 22-250. In an autoloader this can be VERY important to know. One of my AR's has just a slightly smaller chamber than the other. I can not switch the brass between them or one of two things will happen. It will either fail to lock into battery and I'll pull the trigger sending powder all of me, OR I'll notice it, and can't get the bolt open. Now I have a live round that won't fully chamber, and I may have to face the business end of the rifle to get the case out. 2.) Loading these from a magzine may not work reliably. 3.) That case fired ONLY in your chamber, may fail to chamber if the chamber is dirty, and occasionally it may fail to extract.

Thats it the best I can explain it. I tend to use neck sized brass in my bolt actions when I target shoot. I full size nearly all of my AR brass, except for the occasional few that I use when someone tells me I can't shoot tight groups at 150 yards with a semi auto.

Not to steal the OP's thread but I think this pertains. Is the same die set used for Full length sizing and neck sizing or are they purchased separately?