Joe- FWIW-- the late gun 'genius" inventor, John M. Browning, was indeed, a most prescient man- in his era he foresaw the changes in hunting trends in America- The "Market hunters" loved his A-5 shotgun and its clones (Remington, Savage) and some still favored the Win M97 he developed.

So, possibly with those thoughts in mind, he developed the fabled Superposed O/U-- If you have access to a copy of Silvio's "Hemingway's Guns" you can read more of the history of that shotgun.

Hemingway used a "smorgasbord" of scatter guns in his life- Model 12's, a few Browning A-5's (16 gauge) the Superposed he won in a live bird shoot, a Scott 12 bore live bird gun he bought used in Italy (and later had A&F removed the sling swivel clips)--and a few M21's in 20 gauge, and a pair of Merkel 12 O/U's as well-- And in spite of "offside" eye dominance, he apparently shot them well. RWTF

"The field is the touchstone of the man"..