@whatnickname - I don’t expect I can say this in any manner which won’t be taken the wrong way, but here goes...
Case separation is only EXCEPTIONALLY RARELY caused by excessive pressure. It’s almost exclusively caused by excessive headspace (undersizing cartridges). Separations do happen with over pressure charges, but typically are not the sole symptom - and frankly, in over-pressure events, I have more often seen cases hold intact without separating, and swaging themselves locked into the bolt face. So even in a known excessive pressure event, it’s less common to have that type of classic case head separation, which is commonly attributed to excessive headspace.
So referencing lack of pressure signs in the Federal cases is a non-sequitur argument. Case separation in the Hornady really isn’t an indicator of excessive pressure, so lack of pressure signs in the Federal cases doesn’t indicate any difference in strength or quality.
When we walk through the decision tree for troubleshooting a separated case, when we arrive at this point, the question is ALWAYS, “was the case undersized for the chamber? Aka, excessive headspace?” Given your confirmation the case was not undersized, we follow a “no” path, which leads to paperclip testing the rest of the lot on hand to evaluate for incipient separation lines. If more cases fail the paperclip test, then you have a chat with Hornady about a potentially bad lot of brass. If they pass the paperclip, then you chalk the separation up for what it was - a fluke - and go about your business with the rest of the brass.
