Pressure sign during fireforming?

[Kratos]

I’m doing some testing with CFE223 to fireform 6 BRA, and saw these ring marks all around the primer pockets, but no ejector swipes. Is this a pressure sign or just due to the crush fit with the AI cartridge? This was 31.5 grains CFE223, only going 2820 FPS.

 

[MGYSGT]

Primers look round on the edges. Maybe your bolt face is rough and that is what you see.

 

[rardoin]

If you have a proper crush fit you will see marks from the boltface during closure on the cartridge. You marks look like mine in the two Ackley type improved cases I shoot. The primer looks fine. Carry on.

 

[Dusty Stevens]

Bolt face is rough is your only issue

 

[RegionRat]

Which fireforming method are you using? Jam, False Neck, combination?
Sometimes, the marks are just cosmetic and formed by closing the bolt on the false neck or the jam even before the round is fired. Did you have any where the bolt was hard to close or open?

If you have any left that were prepped but not fired, try just closing the bolt on some and seeing if you already scrub the case with the bolt.

In any case, I don't see a pressure problem since the primers are not flowing, and you don't see an ejector imprint. Your load and velocity don't sound risky either.

 

[Texas10]

Some factory bolt faces are horribly rough so this is how I polish my bolt face to remove roughness. I take a fired cartridge case and place some double stick tape on the head, then 500 grit wet/dry. Trim off the excess and chuck it in a cordless drill. I spin that against the bolt face (first remove the ejector and extractor) until most of the pits/flaws are removed, then switch to 600, then 800, then 1000 and you'll have a mirror smooth bolt face. Vacuum out the dust and you're good to go after a light oil application.

 

[Kratos]

You may be on to something. This is my bolt face (you can see the burned ring from a couple blown primers a while ago).

I'm also replacing my firing pin after piercing a primer:

 

[Bc'z]

You can see the shine on the flared edge from rubbing.
Bushing will clean up the bolt face.

 

[Uncle Ed]

The base of the case around the primer pocket might be slightly raised or bulged during case manufacturing. And the raised portion is rubbing the bolt face, and if the shoulder was bumped back .001 or .002 you would not see the rub marks.