“Personally, I don’t see any functional difference between a bump stock and an unregistered drop in auto sear. They both are modifications to a firearm that allow full auto fire. As a side note, at least when the ATF determined that the streetsweeper shotgun was a destructive device, you could still possess one if you registered it as a DD. Also the normal NFA $200 registration (tax) fee was not required.”
Have you ever read the law? What part of it defines a bump stock? That’s pretty important to knowing what you’re talking about.
Well having converted many firearms to full auto with registered drop in auto sears back in the day, not to mention slotted UZI bolts, it is the function of recoiling gun parts (or the whole gun in the case of bump stocks)that causes full auto capability. The part of the law that is relevant is that you are modifying the gun to fire more than one shot when the trigger is pulled. Whether you hold the stock tight for semi or loose for full auto is the same as changing a selector which can be easily demonstrated.