BTW:

Back to autofrettage for a moment;

I forgot to add. I submit, that an investigation of the process of autofrettage MIGHT reveal that in a thinwalled double, OSR is the observable after-effect of autofrettage, and that, in the event, the OSR barrel may be actually STRONGER than it was before OSR was observable. That was the line of thought I was headed for, but forgot to add. The gun could I suppose still be, in effect, "wrecked", due to altered dimensions of the barrel, fitting, etc, but I wonder about this as a side issue.

This might be a rabbit trail, but possibly Omnivourous Bob can comment his own opinion.