PeteM;
You were right, sure like those Pics. Just a few comments. That first pic of the Pieper is like his original patent of 1881 & is usually seen on guns marked "Original Diama"
As far as I know, though I cannot prove it, I think Berretta likely "Coined the Term" Monoblock.
Two other points, while Pieper did not call his "Steel Breech Piece" a Monoblock it in fact was. While you referred to your sawed off breech section as a Monoblock, it in fact isn't.
By definition a Monoblock is machined from a single piece of mat'l & is not joined by solder/braze/welding etc.
Mike; The real purpose of a Doll's head is not to hold the bbls to the frame but to provide reinforcement to the brech against the axial forces upon firing. Actual bolting of the bbls may or may not be incorporated into the Doll's head.
