Hey bowhunthard
A case goes through a transition from new until several times fired. Your new 22-250 cases have a certain amount of headspace, or gap between the case shoulder and the chamber shoulder. When you first fire the case it will expand and close that gap about 85%. During the subsequent firings the case will progressively close the gap until somewhere between the 3rd to 5th firing the case shoulder will contact the chamber shoulder and make it hard to chamber. Generally called a crush fit.
You can continue to neck size in a small caliber like a 22-250 because the force necessary to close the bolt is less than on a larger caliber, less shoulder area in contact with the chamber. The bolt will be harder to close but you will probably have enough leverage to close the bolt anyway.
Between the firing of new cases until you develop a crush fit then you can neck size only (the first 3 or 4 firings). After you develop a crush fit it is best to push the shoulder back a minimal amount for easier chambering and to prevent a problem in the field.
Personally, I prefer to use a Lee Collet for sizing the neck and then a Redding Body Die to size the case body and push the shoulder back .001" or so for a slight crush fit. What I call Partial Full Length Resizing but definitions vary.
Bushing type neck sizers are good pieces of equipment but you need to realize the the bushing sizes the outside of the neck to a specific dimension and pushes all the variations in neck thicknes to the inside of the neck. For that reason they are best used in conjunction with neck turning and without the expander that comes with them. With a consistant neck thickness then you will have less runout with the bushing type dies.
Do-nuts are only discernible with a tight necked custom chamber. It is possible that all cases develop do-nuts but the only way to tell is if your fired brass has an inside neck diameter after firing that is very close to caliber diameter. You insert a bullet into your fired neck and if it will not go past the neck/shoulder junction, then you have a do-nut. In a factory chamber where the neck clearance is larger than .003" the do-nut will not protrude far enough into the neck to stop the bullet, so it will have no effect anyway. You can not get rid of do-nuts with a die, you have to inside ream or cut them out some way or other. Anyway, if the bullet passes by the neck/shoulder junction in a fired-unsized case then the do-nut (if there is one) will not contact the bullet after sizing, so it is a non-issue.
I have 4 tight necked rifles and turn for .003" clearance on all of them but only my 280AI develops do-nuts. Don't know why, just the way it is.