This overstressed rifling/mono bullet deal is something I have been attempting to research for a couple of years now.
There is a lot to it all that's for sure, and I can tell you that what you are looking at here at the moment, is IMO just the tip of the iceberg.
It is easy to get caught up in all this business about the monos being difficult or impossible to push through a drawing die in a reloading press bolted to a wooden bench, but how relevant is this compared to shooting those bullets in a double rifle?
Someones bench started to split when he was trying to push a mono type bullet through a reducing die in a reloading press which normally can easily swage conventional bullets without difficulty.
My feelings on this is, ok, so it proves that the mono is harder to reduce than the conventional bullet.
No surprises there, surely, but does the split bench point to broken rib joints and OSR on double rifles?
To me all it really proves is that reducing the diameter of the conventional bullet is within the capabilities of that particular press/die/mounting system but the mono is beyond it.

9Three,
I'm pleased to see that you brought up the fact about the bullet being engraved/sized in the heavy barrel section forward of the chamber.
For a couple of years now I have been having a chuckle every time the super thin DR barrel theory (being a contributing factor of OSR) crops up.

But, like I said, there is a lot more to the story.