Thread: excessively tight primers

I was loading some new Nosler 7mm mag brass the other day and one pack of primers were tight, the next lot is excessively tight i.e, I cant get them to seat fully for fear of them going bang! CCI Magnum primers is what I'm using, I have found some variation in sizes between brands but never between packets of the same primer and never to the extent that I can't seat them.