I found two articles written by A.P. Curtis in the American Rifleman magazine. The first article "The advantages of short chambered shotguns" can be found on page 14 of the July 1936 edition. His second article can be found in the March 1938 edition on page 21 "The advantages of short chambered shotguns - Part 2".
Interestingly enough it was in 1937, in between these articles, is when SAAMI met and established chamber standardization along with its strong warning about the dangers of composite barrels. Was his first article the impetus for the 1937 SAAMI meeting?
What I took away from it, several manufacturers were producing guns with chambers 1/8" to 1/4" shorter than the intended shells along with the advent of the 3" 410 being shot in 2.5" chambers. This was done not for a better gas seal, but for less disturbance to the pellets entering the forcing cone. This was proven to improve patterns as the paper shells provided a cushion and seal as the pellets met the constriction of the bore. He cites some championship trap shooters who were using 3" target loads in 2 3/4" chambered guns. Longer shells in shorter chambers was not recommended for composite barrel guns. They could also cause a problem with early ejector systems. A nominal increase in chamber pressure of about 500 psi would result.
The two articles are a very interesting read and explain away any debate and mystery about short chambers.
Both articles can found and read here:
https://onlinebooks.library.upenn.ed...Wq1WBiaFhpps7M
The history and science of short chambers
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