OK, I'm with you now- if you want accurate historical information on 19th Century U.S. Firearms, go to a UK gun dealer/auctioneer. You might consider consulting published U.S. authoritiea at some point. Just a suggestion.

Now, these types of multiple-barrelled weapons MAY be referred to as 'paradox' guns in the UK (other than by this one dealer) but certainly ain't so on this side of the pond.

Perhaps you could clarify what the term "paradox" actually means to Messers. Long, as they apply it to a regular back-action lock double percussion shotgun, an over-and-under side-hammer (or mule-ear)
rifle/shotgun combination gun, and the three barrel swivel breech combination gun originally mentioned.

Also, nowhere do Messers. Long comment on the history of these weapons, or how "common" they were at any time or place. And they don't call 'em "drillings".