Factory Ammo Popped Primer Follow Up

[PeteS]

I purchased the brass from the OP, and sized it this morning.  What I should have done was recorded the lot numbers from the boxes, assuming that it went back into the original boxes...but examined the primers knowing that the brass had been fired in two or three chambers.  I noticed that ONE case fired in a gas gun had a pierced primer, and one particular box fired from a boltgun seemed to be more pierced than not.  There were both brass and silver primers, and MOST were flat.  There was a box or two with brass primers that had rounded shoulders, so appeared as I would have expected if loaded to gas gun pressures.  NONE of the cases sized hard or showed ejector plunger marks.

I've chrono'd different lots of Hornady Black side by side and saw ~100fps difference between boxes.  IMO, Hornady's 6mm ARC ammo seems to vary considerably, and I suspect that the flat primers were literally thin cups, and the round shouldered primers were AR spec primers with thicker cups.  Too, I've heard that Hornady is switching powders and not just different lots of the same powder, so would also contribute to velocity variations from ammo lots.

All the brass fired that was sold to u from me were factory rounds and were fired in a Savage Axis 2 so no gas gun. And they were the same original boxes and brass together to keep lot # together. There may have been only 1-2 boxes fired from my new Shaw Barrel, the rest were from the factory savage barrel. Not sure which lot numbers for each barrel, but I already sold all the brass shot from my AR years ago but none to u. But what was weird to me is Hornady factory loads should be loaded to AR pressure specs but look like they were hot like from the Bolt gun specs. But Hornady couldn't, or shouldn't, do that without lettin people know. Thanks, Happy New Year.