Most sabot slug ammo boxes will tell you if you need a fully rifled barrel or just a rifle choke tube.
I had a rifled choke for Remington, no luck with 5 different ammo.
Threw a cantilever rifled barrel on the Mossberg and at 110 yards I shoot consistent 2.5 - 3 inch groups.
My buddy use to use the challenger rifled slugs in his 870 fitted with a side saddle scope mount (not the best for accuracy) and he has shot deer out to 160 + yards. He only switched cause his son started hunting and needed a slug gun. Sonny got the old one, Dad got the new one.