Thank you or all the suggestions. This is a Christionson LR Mesa. i had check the brass length, COL and head space. No change on dies.
Finally tried new brass and no issue. Back to 1/2 inch groups at 200.
My current theory is that my primer pockets are getting loose. Maybe the loads are hotter than I had though, but never has any issue before. 5th firing of brass and I think they finally gave out. Allowing some pressure to pass back though the flash hole, around the primer. was even burning out the primer pocket. this was pushing the primers and making the bolt sticky. Its all I can come up with, nothing else was different.
Regardless the new brass has fixed the issue.
Thanks you all for the input.
How many firings should I be able to get out of new brass? Assuming I'm not running to hot of loads.
How often are you annealing?
You should be able to get at least 10 firings from Lapua 6.5 brass. Even up to 15 firings or more possibly.
Neck wall thickness has been mentioned a few times but you have not responed to that unless I missed it. It's a known fact Lapua brass is thick and can cause your issue.
Have you done any measurements or tried sliding a bullet into a fired case yet to check clearance? You're question may have been answered on page 1 a few days ago.
Also, measure the outside neck diameter with a loaded round seated into the case. Then measure a fired case outside neck diameter. See what the difference is to get an idea of adequate neck clearance in the chamber.
Doing the same measurements on your old brass you have had problems with will really help narrow down what is happening.
That's exactly what you need to do next...
I have tried sliding a bullet in, and real issue. I get a tiny bit of friction, but nothing much. Its about the same as the new brass.



























