Oops, I overlooked the link.   
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Even a birdshot shot exception has been found to occur in extremely slow twist,   (1 in 144"), muzzleloader barrels of the Forsyth pattern.  Best patterns occured with the use of a steel shot type shot cup, (using lead shot), and a droge or drag to mimic a the action of a Flite-Control wad.

See this article on modern repoductions of the Forsyth underhammer for more information on shot performance in ultra-slow roundball twist rifles.

http://underhammers.blogspot.com/2011/09/forsyth-rifling-forgotten-magic.html

At one time you could get chokes for smoothbore shotguns that had rifling in them to allegedly help stabilize slugs.

There are still a few rifled choke tubes available on the market, although the popularity of these tubes seems to have waned in recent years.

The BRI sabot slug,  now marketed by Winchester, is one of the few sabot slugs that has a reputation of working quite well from both rifled choke tubes as well as fully rifled shotguns.  I think this is because the BRI was originally designed back in the 1960s for smoothbore use and actually predated the modern rifled shotgun.  The nose heavy design combined with moderate velocity levels seemed to be the right combination to make rifled choke tubes work.  That is probably why the BRI design is still in production. 

Here is a 2014 article from the American Rifleman about the BRI design used in both fully rifled and rifled choke tube shotguns:

https://www.americanrifleman.org/articles/2014/3/7/winchester-super-x-bri-sabot-slugs/