I am wondering if anyone has had this problem. I have just bought a new case of lapua .243 brass after just one firing I find I can't get my resizing die all the way home. I had no trouble with Winchester brass. Any clues?

it could be the de-cap pin is bottomed out?

Are they lubed properly

Sorry I meant Lapua.

All lubed and even tried taking de primer out. They actually measure larger than the Winchester at the base.

does the resized brass fit the chamber of the rifle? What about the oal of the brass?
have you been shooting over max loads in that rifle?
It may have developed a head space problem, causing the case to bulge at the base. any loose primers?