John:
Regarding your posts above on Howdah pistols, the "elephant in the room" (pun intended) is the top-lever.
A howdah cartridge will generate recoil, especially if used one-handed in haste, and the top-lever will likely split the web of the thumb on the shooting hand.

Pedersoli's remedy is ugly as hell, but clearly designed to circumvent litigation.

The best remedy of course was an under-lever or perhaps a side-lever opening.
...and lack of the top-lever further circumvents the suspicion of a sawn-off shotgun.