I don't think anyone here has enough experience to say that. If you look at muzzleloaders, nobody with a modern 1:28" twist gun is getting their best accuracy with a round ball or conical. Look at Taufledermaus on youtube, how many slugs has he tried now that are stable from a smooth bore, but practically tumble in a rifled gun? Two or three at least. Rifled choke tubes absolutely work, and I think Longbow is right on the money. Unfortunately in this modern day of $5 per shot sabot slugs nobody will care, but a slow twist rifled choke could be wonderful for rifled slugs, or other full bore slugs.