Another option, what I would do, is neck size only with brass fired only in that rifle. Assuming brass fired in that rifle will easily chamber, neck sizing will give you better case fit and better case life, as you are working the brass less. Try neck sizing a few rounds, and if chambering is still difficult, then experiment with screwing the die down a little at a time until you get easy chambering. A picture of where it is rubbing would help. I still have a sneaking suspicion the neck expanding ball in the sizing die is sticking, causing the case to either slightly collapse or stretch, causing the problem you are having. I always lube the inside of the neck with a dry powdered lube that slickens the expander balls pass thru the neck without effecting the powder.
Larry