Sometimes, a rifled choke tube works wonders with accuracy, but sometimes they don't prove as good as a plain smooth bore. You never know until you try one!

I had a 12-Ga.Ithaca Deerslayer once that was actuallly boredto about a 14-gauge diameter for whole length of the bore. The best shooting slugs in this gun were those of .690" that came in the Remington brand. They just fit the bore tightly! That smoothbore was able to shoot 3", 3-shot groups at 100 yards (it had a 2.5X scope on it).

Today, I would get a couple of different slug brands,take one shell apartof each make, and see which brand slug fit tightest in one of your choke tubes. I would then use that brand with that choke tube and test to see how it shoots.

IF the slugs gave a tight sliding fit through the tube constriction, I'd bet they will shoot tight groups (3"-4"@75 yards).