Re the quote about 2 3/4" chambers post-1957 . . . as a former owner of one each Standard 16 and Sweet 16 made before 1957, I can verify that they handled American factory 2 3/4" shells without the least problem. That would not be true if they'd been chambered for 2 9/16" shells, because it's not only a question of the chamber, but also of ejection, etc. And if none of the 16's made prior to Jan 57 were 2 3/4", that would mean WAY more short chambered 16's, both Sweet and Standard, floating around than 2 3/4" guns. About 300,000 of them, not including the pre-war guns. By the late 50's and 60's--which was long before the current interest in short-chambered guns--I'm not sure where anyone in this country would have gone to buy short 16ga shells for those guns, and that's what they would require.
I have no doubt that FN continued to make short 16ga A-5's long after the war. 16's, many of them still short-chambered if not made specifically for the American market, were still quite popular in postwar Europe.
