9.3, autofrettage is exactly the process I was thinking of when I mentioned buttoning full diameter blanks. I think this might make them possibly be less susceptable to OSR? I know some modern production doubles use buttoned barrels in addition to having fairly heavy contours. I wonder if this contributes to some production makers saying monos are ok in their guns. Given a choice I still prefer cut rifling, preferably of the chopper lump variety!

Also, I speculate that the condition of the lands at the throat could make the situation potentialy worse. Nice new square lands perpendicular to a bullet band should shear through it. A worn throat could present a taper, in effect squeezing the land into the band/shank. Not a big problem with a compressable lead core bullet, but squeezing would present far more radial pressure than shearing.
As an analogy, the lead face of the thread on the ice screws I use is tapered because the goal is to NOT shear the ice, but rather displace it gradually under pressure.

I think this would be interesting to experiment with out of curiosity, but as others have mentioned wouldn't ever take a chance with a double when legal alternatives are available.

If you talk to Col. A2, I'm really curious about that "Weapons Systems Engineering" degree he mentions on his book jacket.