Thanks, Gatsby...I'm understanding that when talking about a "Paradox gun" it is a period gun rather than a modern gun even though H&H will make you a modern version...for a LOT of money.

NO rifled gun will pattern shot very well...the spin will open up the pattern more than a standard choke will and a 4 petal wad will worsen the pattern...argumentatively speaking. The rifled chokes tubes I have equated to ~IMP CYL and 1/35 twist...OK for game birds up close and a pie plate slug group at 75-80 yds depending on slug length...I gave up wasting shot and went back to mod/full chokes, and a fully rifled barrel.

Turning and honing out the rifling and leaving 3-6" of rifling would be a giant waste of time but if done right with a bit of run in for the shot/slug shouldn't be too hard and should shoot just as well as a "real" Paradox gun. Getting the smooth bore section the correct ID is no problem...just deep hole drilling so to speak. I couldn't do it with my loosey-goosey lathe...bed isn't long enough besides.

Interesting problem to solved though.

You shouldn't shoot slugs through a choked muzzle even with modern steels unless the slug is sized correctly...even cylinder bore choke tubes have a range of constrictions running from ~0.725" to ~0.735" Nominal bore ID for the 12 ga is 0.729" but some of the back bored shotguns are much larger so you need to measure to be sure. But you all know this.

This Paradox gun "which slug to use" is interesting and adding to my learning process...Thanks everyone.