Humpty Dumpty,
He obviously did not succeed. However his view about the barrel atachment to the receiver via a through pin is interesting.
A friend dealer has a large stock of pre WWII shotguns, about 400 in total. Looking through them I realised that the folders seemed to be holding together surprisingly well considering their condition and obvious use. Additionally, most of them are not quality jobs, just average Spanish and Belgian folders with a smattering of mostly converted Rook rifles.
I had to go back and review all the engineering assumptions about the behavior of actions and the stresses involved on firing. It looks like most authorities have skipped over the Poisson effect in thick tubes. The chamber area of a shotgun is technically a thick walled cylinder, so on firing there is radial stress and axial contraction. Logically contraction is followed by expansion to normal dimensions in the recovery phase.
I suspect, and this is pure theory, that the rapid (milliseconds)expansion-recovery of the chamber section is responsible for shotguns coming loose. THe through pin of folders seems to prevent this result. Again, this is an unproven personal theory.
