"ATF has previously determined that attaching the brace to a
firearm does not alter the classification of the firearm or subject the firearm to National Firearms
Act (NFA) control. However, this classification is based upon the use of the device as designed.
When the device is redesigned for use as a shoulder stock on a handgun with a rifled barrel under
16 inches in length, the firearm is properly classified as a firearm under the NFA."
https://www.atf.gov/sites/default/files/assets/Firearms/FirearmsIndustry...
Using something in a different manner does not "redesign it."
Under this crazy decision, American citizens would be guilty of a federal offense for holding an item the wrong way.
Turn over this decision now.