2Piper,
The barrels, i think a Mossberg pump barrel, in the BB demo is tied to a bunch of thick tree branches, and in recoil drags them back a fair distance.
I have seen and personally photographed a few receiver crackings in SXS doubles. I have yet to see an OU cracking its receiver.
Again, there is the total lack of reference to the Poisson effect, (the radial expansion and axial contraction, and RECOVERY of the chamber part of the barrels), in the various analyses I have read. And how the Poisson effect may contribute to these frame crackings.
I do not discount the pressure of the cartridge on the breech face, but is it the only part exerting pressure on the breech face? And what happens when the frame recovers from its flexing and it in turn squeezes the barrels betwen breech face and cross pin? It would seem that flexure recovery turns the barrels into a piece of "work" caught between breech face and cross pin and this may be happening when the barrels are recovering from their momentary expansion-contraction.
The strength of the locking system in a break open gun seems to be secondary to the other elements contributing to the strength of the action. Other "bits" seem to be more directly involved.
