@Smokin Joe
Thank you for the explanation. I have never heard of a rifled slug. Never experienced this law.
For me a shotgun has always been a fast reaction point and click. Never considered them for downrange targets.
Now I know.
My dad, who has been known as a consummate marksman since his service during the Korean War, harvested a whitetail at 250 yards with a scoped shotgun (slug barrel) and a sabot slug. While that's considered a middlin' rifle shot in these parts (I'm 2000 miles away in shortgrass prairie), in the fields of Southern MD, that's considered remarkable, not only for distance, but that he had a clear shot that long. Apparently the deer was acting unconcerned and standing still, likely not expecting to be shot at from that far away.
Shotgun only areas are common in MD, NY, and MN, and may well be present in other states.