IMO, not much. With situation like this, you limiting factor is usually the bead on the smooth barrel. Not good for pinpointing. but if you have rifle sights, you could see a significant difference or none at all. I tried this, and I was hitting a paper plate at 50 yards with rem sluggers and modified choke. Then tried the screw in and copper solids, and was still hitting the plate. Nothing earth shattering.