Re: OK I need help!
I checked out brassmanbrass.com and he advertises once-fired Lapua brass. I wouldn't jump to the conclusion that his brass is fired more than once, but I'd say at the very least it was fired in a chamber that was looser than yours.
Just ahead of the web the brass will swell. FL sizing doesn't always bring the brass back down to spec. This is more of a problem after it ahs been fired 8 or 12 times and begins to work harden.
I have witnessed this with my rifle and there is no cure for it that I know of. I usually get about 10 firings on my Lapua brass but I've gotten as many as 16 firings. Once they harden to the point that they are difficult to extract, they are done.
I would suggest you buy some new (unfired) Lapua brass and I expect your problems will be over, at least until you have 8 or 10 firings on them.
I have thought about looking into buying a custom small-base die to see if I could extend the life of my brass but it seems that after 10 or 12 firings that I've got my money's worth from them.
Good Luck, Festus
"Fenced yards ain't hole cards and like as not never will be, reason for rhymers and old five and dimers like me."