Mike...if your case is undersized it will be evident with the Wilson case gage. Also, if your case is oversized it will show that too.
WRT "futuretrades" post. What he wrote is what I have had to do in some instances. If I screwed my size die down until it touched the shell holder and then backed it off 1/4 turn (or so) odds are it wouldn't chamber in my rifle(s) either. If you screw the die down until it makes contact and then screw down some a little more (1/4 to 1/2 turn or so...) and it worked, I would be OK with that. However, the potential downside is it could be a tad hard (depending on how far down you have screwed it) on some of the pins for the press. That is why I won't go beyond 1/2 turn further down.
If that still didn't work I would one of two things:
1. If a lathe is available, take some material off the shell holder or get a set of Redding off-set shell holders. Those are the only other ways (in addition to the above) I know of, off-the-cuff, to get the shell holder further into the sizing die. In fact I would just get the shell holders from Redding because they are hardened. Taking material off of a shell holder may mess with the hardening "plus" it reduces the material and probably the strength of that portion of the shell holder that grasp the case head thus breaking the shell holder and possibly the case head too. If that were to break there goes the shell holder and if it broke the case head rim, the size die is OOC until a stuck case removing tool is procured.
With respect to oversizing; "Oversizing (squeezing the brass down too much) can creating an "excessive" headspace situation. If a measuring device isn't in the works, you would need something to prevent oversizing. Excessive headspace isn't a good thing for obvious reasons plus, it significantly reduces the life of the brass. Maybe only once-fired, if it's too bad

. If you have a 308/30.06/223 I would invest in a broken case extractor. I need one for 204 & 6mm myself.
Creating a little more