What do they look like under 20X magnification? A raised ring around the primer dent? Pull a primer and remove the anvil. Look at the inside of the primer. Do you see a "moat" around the raised primer dent? Your primers still have rounded edges, and do not appear "flattened". They appear to be Federal with 'FC" visible. Are you using brass saved from off the shelf ammo?. American Eagle? Did it have a crimped primer? Good stuff.
Any pressure, low or high is going to try to move the metal cup into the space between the firing pin and hole it protrudes from. If this gap is more than .002, you may see these "classic signs of pressure" beginning to form well below max operating pressures. CCI cups are thicker than WSR and are nickel plated. BR-4 cups are thicker still, and so are CCI 450's.
My 12FV in 223 was experiencing cratering (also called partial blanking) and perforation of the primer (also called blanking) at loads in the mid range of load charts using CCI-400 primers. Upon close investigation I found the firing pin was undersize by .0025 making the gap between the bolt head and firing pin .007. WAY TOO MUCH!
You can pull the firing pin and measure the tip with a micrometer. To measure the hole in the bolt head, you can use a selection of drill bits, carefully measuring the shanks to get a very close idea of the fit to the hole. Or buy or get access to a pin gage set or have your machinist or gunsmith measure it for you.
You can order a firing pin from Savage by signing a release of liability.
You can also have your bolt head bushed to remove excessive clearance. All depends upon how much coin you have available.
Other things that can raise pressures and cause primer issues are seating the bullet too deep in the case, seating the bullet into the lands, using Military brass (which is thicker and therefor has less internal volume), leaving the loaded rounds in a hot environment, or a hot barrel. And about a thousand other things.
Varget or 8208XBR will also work well with that load.
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