I think Burrard may be missing something, at least on our side of the pond. If the standard length of the case didn't reach 2 3/4" until after WWII, then why would all American gunmakers have standardized on a 2 3/4" chamber length for 12-16-20-28ga guns prior to WWII? We've discussed the wide variety of shell lengths that existed prior to WWI. However, at least according to my 1940 Shooter's Bible, those had almost entirely disappeared by WWII. You had the old, standardized short lengths of 2 5/8" for the 12ga, 2 9/16" for the 16ga, and 2 1/2" for the 20ga, and then you had 2 3/4"--the "new standard"--for all 3 of them. And I believe that the last gunmaker to switch to 2 3/4" as standard was Hunter Arms (LC Smith), which had stuck to the old 2 9/16" 16ga standard until about 1940.
