I believe the India pattern Land Pattern Sea service ran 37" brl there where some shortened besses to fire grenades, Next come various Cavalry, Artillery, Dragoon & Sargents carbines at 37" the first pattern Royal Foresters ran 30"then 28' Elliots ( & later Royal Foresters) any shorter where not meant to take B nets .Nor where any that where' home stocked ' full wood to the muzzle obviously. All' Carbines' being carbine bore 16 bore not full 75 or so musket .even the 42"brl 1760 Light Infantry is still a 'carbine ' By the' nature' of its issue. Whether you would call them' Besses ' ? certainly same family & stable . I may have missed some its from recollection . There where no doubt oddities & you get variant Commercial arms . and its not unknown for muskets being shortened for various reasons but none likely to be for the Indians . What traders might do with surplus arms who is to say but most trade guns seem to follow a distinct style . What traders peddled in Africa & other markets ?? No saying . There where over three million Besses made of India pattern and for years after the surplus Besses went every where a dog barked. Many to New Zealand . The Maori took to them with pickles and about polished off many rival tribes in the course of about 30 years of intermitant war . & the New Zealand Company brought many for trade or defence . along with 1796 Pattern Dragoon sabers & B' nets , Axes, ect (And you thought the West was wild!) Any way I digress I do Ime getting old! .
Regards Rudyard