For the most part I would steer you away from dies with neck bushings. Not that all bushing dies are bad, but some do have some problems. I have found that most bushing dies the bushing floats around inside the dies, and throws concintrisity off. The other problem is most bushing dies don't size the whole neck. The problem is since the bushings don't size the whole neck, the brass has no were to go, but to form a donut above the shoulder. I would get a dies that pushes the shoulder back.

If you still feel that you need bushing dies, I would suggest you look at Neil Jones, Harrell, Bruno Shooting Supply, and Forester (should bump), dies. They all use a method to tightly hold the bushing, and bump the should back. Other dies do not.

The way you determine neck sizing is: first you need to know the size of the reamer like a .250 neck 22br, or a .262 neck 6PPC. Now this is the controversy, some people say .001 Clarence is enough, and others say it is too tight and will throw off groups. Most people say .002 is right, and some say .003 is perfect. Once you have decided how much clarence you want. (say .002 then you would need a bushing that gives you the desired neck tension.) Most people say .002 neck tension is perfect. So if you have a .250 neck you need some Clarence like .002 making the measured case with bullet seated at .248. The if you put .002 neck tension you will need a .246 bushing. You would need to cut the brass to .012. with .012 x2 sides you get a .024 thickness add that to the bullet diameter, (.224) and you get .248. Hopefully this is clear as mud.