An observation only......
I have owned some (5) shot several more (7-9) Boss O/U guns of various ages and configurations........ The trigger firing order (regardless of the choke constriction/firing sequence ordered) in Boss guns was almost universally made with the intent of firing the TOP barrel First..Just a Boss thing.....Various rather knowledgeable souls of an earlier era with much more experience than most of us here gave varying reasons..... Not the least of which is the ease of reloading after a single shot was fired ( whether by the shooter or his loader)....
A gun that I have, or rather had,rather extensive experience with was a Best 30" dedicated Pigeon Gun originally in the book as delivered with ordered F&F tubes and Boss single trigger...
Circumstances dictated its rather emergency sale by the original owner and it resided for two plus decades with a well known Texas ATA luminary and keen flyer shot..... His desire for it to shoot Bottom-Top led to the installation of a Non Selective single by the well known Miller Bros.
The double trigger game guns I have owned , both 12 and 20 gauge were sequenced to fire the more open choked tube ( top in each case) with the Front Trigger....
My experiences are borne out as pretty typical when discussing same with friend and knowledgeable British Gun "expert" Cyril Adams.
