Consider that some of the Westley Richards Fauneta guns and the J&W Tolley Ubique, although very similar in function to the Paradox, did not have rifling in the classic "lands and grooves" sense. They employed oval-bore rifling like the Lancaster, but only out at the muzzles which also worked very nicely as a choke for the shot charge.

I'd really like to get some cerrosafe castings of the muzzle ends of Tolley Ubique and smooth-tubed WR Fauneta guns.
If anyone here owns a Tolley Ubique or a Fauneta with the smooth chokes, speak up. I'd happily have some Cerrosafe drop-shipped to you for this purpose.

--Tinker