I had the same thing happen to me around 1974 with a bad batch of Remington 9 1/2 primers that were recalled.
Remington replaced the bolt at no cost to me because the primers were defective.
Any time you see a primer let go at the edge of the radius it means the cup was weakened when the the cup was formed.
Meaning the brass cup was too hard and bending the brass 90 degrees to form the cup weakened the radius.
Remington and Winchester are no longer what they were in the past and they both went down hill after loosing the contract to make ammunition at Lake City.
On top of this Winchester sold off their brass manufacturing plant and now buy their brass from the cheapest bidder.
Bottom line, no more Remington/DuPont and Winchester/Olin and they were bought out by large stock holding companies.
Example the DuPont IMR-powder plant in Canada is now owned by General Dynamics Weapons Division. And I think the Winchester powder plant in Florida is also owned by General Dynamics. And ATK owns most of the other primer manufactures.
https://vistaoutdoor.com/brands/
Note, I loaded my .270 with the same load you are using and the only problem I ever had was from one batch of bad primers. I would contact Winchester and see if they will repair or replace your bolt if it was damaged.
I use a Lee depriming tool to check for loose primer pockets, and if the primer moves with just finger pressure the case goes in the scrap brass bucket.