hmmm. How does a rifled slug gun pass muster?
I hope you are not asking me to explain the "common sense" behind BAFT regulation! I am not up to that. I am not even sure God could figure it out.
Click here for definition of Destructive Device
As you can see from the definition, for some reason shotguns don't count. Go figure.
Click here for federal destructive device definition
This has the punctuation right, so that you can see that a poison gas bomb is a destructive device, even if it has only 3 ounces of propellant.
Again, please don't ask me to try to make sense of these federal laws.