This is very interesting, I am shooting the same rifle, 12fv 223 cci 400 with 24-25gr varget 69gr smk and my primers look the same as yours. It don't matter where I seat the bullet.
I had a couple guys of more experience look at my primers and they said the pressure was fine.

I am thinking soft primers, I am going to try thicker primers and see how that goes.

25gr of varget seems to be the sweet spot.