Are you using Norma brass? It is often quite soft, in my experience.
Where you are measuring is also important. If you are measuring just ahead of the web, with a blade micrometer, .003" indicates something is seriously wrong. If that is the situation, I would discontinue all use of the rifle and take it to a gunsmith.
I suspect, though, that you are measuring some other portion of the case, probably with a standard micrometer or dial caliper, and are seeing the typical expansion one can expect of the lower portion of the case body.
For what it's worth, I don't consider case head measurements a good gauge of pressure or safety. There is too much disparity between individual rifles and individual brands of brass. Especially now that we have cheap, reliable chronographs, I have given up measuring case heads.