Many thanks to all those involved, and especially the gun owner, with whom I have spoken and who graciously agrees to ship the barrels to me for an evaluation
The gun is a 1908 Reg. frame 16g No. 0 L.C. Smith with fluid steel barrels.
The shells were Cheddite for Herters "Select Field Dove and Quail" 1 oz. at 1165 fps, or the old 2 1/2 Dr. Eq. I have no pressure data for that load, but similar loads run about 9,000 psi.
The gun has been used regularly since purchased 2 years ago. The chambers have been measured at 2 3/4"; suggesting the chambers have been lengthened unless the barrels are so marked.
The blow-up occurred on the Sporting Clays course. The shooter did not perceive anything out-of-the-ordinary before or with the blow-up; other than the load report in his ear. No increased recoil. A piece/pieces of barrel struck the tree to the right but was not recovered. I failed to ask him if there was any chance that a 28g shell could have been in his vest, but will do so.
Images courtesy of Dr. Jim, which I believe show a ring bulge at the forcing cone suggesting an obstruction
The shell used at the blow-up. Clearly the Cheddite hulls have a separate plastic base wad
Fortunately, the shooter has the 6 hulls used immediately before the blow-up, and believes the base wad is present and intact in each.
He will send me the barrels, the 6 shells used before the blow-up, the blow-up hull, the remainder of the unfired shells, and the shell box.
Almost never do we have an opportunity to analyze an event like this, and can always learn something when we are able to do so. Stay tuned!
