I don't have a scope on mine... just fiber optic sights... They do well for an 870..
I have had good success with the winchester super-x bri sabots! The groups are 3inchish off the bench (3rd) @ 50 yds with open sights.. The win supreme partition golds do good, but I have trouble shooting more than one or two... 1900fps is hard kicking!!! I think I could do better with a scope...
My buddy has a boltacion rifled slug gun and swears by the lightfields... and they have wonderful reviews..
best investment on a shotgun is , trigger work, recoil pad (I like mySimms ), sights... by changing from factory rifle sights to fiber optics, new recoil pad, and a trigger job, I cut from 5-6 in groups @50 yds to 3ish...
Hope it helps and good luck