I fired quite a few rifled slugs, mostly Remington and Federal, through a Mossberg 500 Pursuader pump gun at man-sized silhouettes at 100 yards. This shotgun came with rifle sights for firing slugs.
They were surprisingly accurate for me. But I was firing mostly from a prone position with the shotgun laid over a duffle bag.
It was just my experiment to see what the slugs would do out of my Mossberg, and I could generally keep them all on a small paper plate at 100 yards. Not very good in terms of MOA precision, but adequate for hunting. I suspect the slugs would start dropping off as you went out to 150 yards, but I only had a 100 yard range to work with. Perhaps someone who is a better shot than I am could achieve tighter groups.