Will try again and start the summary thread here as the format on the LCSCA Forum makes it hard to follow long threads with multiple replies.

Many thanks to all those involved, and especially the gun owner, with whom I have spoken and who graciously allowed this evaluation. I freely admit that my initial assessment was wrong; there is no obstructional ring bulge, and the gun was not the victim of inexpert chamber/cone lengthening.

I claim no metallurgical or engineering expertise. My information comes from conversations with the metallurgical engineers at METL and several gunsmiths in preparation for “A Blow-Up Post-Mortem”, published in The Double Gun & Single Shot Journal, Vol. 27, Issue 3, p. 17, 2016
and summarized here
https://docs.google.com/document/d/1ZnptAPvQIlWG5n5UU2FmKcFpYtVmOSc4b7K7G9IBs4g/edit

It doesn't take a lot of brains or talent to record wall thickness numbers; just the equipment and practice therewith to establish repeatable numbers and the willingness to spend the time to do it right; and it does take time.

The gun is a 1908 Regular frame 16g No. 00 L.C. Smith with fluid steel barrels; though without the usual “Armor Steel” barrel mark; it does have a faint 'C' we believe for Crucible Steel but no SB&Co.

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 hang tag that came on that gun listed 2 1/2 dram 1 oz. shot, and Nitro powder loads then had similar pressures as today.

The gun has been used regularly since purchased 2 years ago. The owner states that the chambers have been measured at 2 3/4”.

The burst occurred at the 2019 “Southern” on the Sporting Clays course. The shooter did not perceive anything out-of-the-ordinary before or with the burst; other than the loud report. No increased recoil. A piece/pieces of barrel struck the tree to the right but was not recovered. The shot through the barrel immediately before the burst was normal; no FTF or soft report.

Images courtesy of Cheryl Stubbendieck





Note that the rib has been lifted

Thoughts from Dewey Vicknair



Hunter Arms used a brazed hook and rib extension; courtesy of David Elliott



and the wall adjacent to the wedge hook piece and top rib extension piece are flat

12 gauge



The subject 16g gun