I don't care what load, federal primers will flatten no matter what. They are not a good indicator. When you see the primer so flat, you can't feel the difference between the brass or primer with fed primers, its overloaded
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As I posted above, I fired two shots with this ammo, and both blew the primers out out of the case. I had to pry the bolt open, and the case heads were shaved by the extractor groove.
I don't doubt that I reduced the loads more than I needed to. I also don't doubt that they were way, way overloaded the way they were.