I guess I'm not confident a Browning or a Beretta wouldn't show the same issues you found at 250,000 shells.....on your Perazzi .../maybe worse...I don't know ??
But I'm still having a hard time quantifying how much of that wear on the breech face would be from reloads vs factory shells. I guess the only way we'd ever know would be to have two guns ...one fired exclusively with factory shells and one exclusively with reloads ...so we probably just have to take the word of your Perazzi service center rep / on what he says caused the issue.
I wonder if the breech faces on some guns are hardened to a different level than others ...or machined to tighter tolerances ...and how all that fits into the equation / if it even does. I think I may have napped during some of those strength of materials classes ...but if its "too hard" ---that's bad too, I would think ...maybe causing it to pit more ...but I'm out of my league now !!