Sounds like you may have too much neck wall brass.
Since the empty cartriage chambers ok, and I am assuming you are using a quality factory bullet that mic's out at the appropriate diameter then here's what's happening and how to fix it.
The resizing die (either neck or full length) is sqeezing the outside of your neck to a diameter much less than necessary, then the expander ball, on the upstroke is stretching your case neck to the size the die maker felt was correct for your application. Typically an inside diameter of about 0.002" less than the outside diameter of the bullet. None of these things have address the thickness of the case neck which grows after every firing.
Generally the effect is not noticable for the first few firings of a case, but in the case of a tight necked chamber (a good thing!) and thick walled brass it could happen on the first reloading.
The correction is to either inside ream or outside turn the case neck to a thinner thickness. I have found that with outside turning it is much easier to control the amount of brass that is removed. Inside reaming will sometimes be necessary to remove "The Dreaded Doughnut" which is a region near the transition between the neck and the shoulder on the inside where outside turning can't reach, that may become quite thick. If your bullet doesn't touch this area then it has no noticable affect, but if the seated bullet does touch it, most likely it will show up as increased outside diameter right at the neck shoulder junction after the seated bullet forces the excess to the outside. Should only happen with heavy for caliber and/or flat based bullets.
One last thing - remember that if you turn 0.001" off of the outside you have changed the diameter by 0.002" (half on each side).
Hope this helps!