I have a 12 LRP 6.5mm Creedmoor that would show high pressure signs with factory ammo, and hand loads at 57,000 psi, 47,000 psi and 37,000 psi.
Primer pockets were completely worn out after 4 reloads.
It shot incredibly accurately but it sure was hard on brass and primers.
I carefully recorded the results, took pictures of the brass with flattened primers and of the primers after they were deprimed along with the loads.
The key issue for Savage was the factory ammo that was flattened enough that you could see the head stamps were flattened.

After talking with them and sending them the pictures, they had me send back the rifle and bored out the chamber a few thousandths.
I have actually gotten 25 reloads with Lapua brass and small rifle primers. That could have never happened with the initial factory bored chamber.
That solved the problem. Even better, it shot just as accurately as ever. I now shoot 57,000 psi loads with the primers still rounded.

I now have over 4,000 rounds through the LRP and it still shoots as accurately as it did when it was new.

I think you and I both got chambers bored out with worn reamers.