. On August 27, 2009, Jesus Amador, Jr., was arrested by an undercover officer when he sought to sell his Heckler and Koch SP89 pistol. But, one can legally sell an H&K SP89, so what’s the twist?

Unfortunately for Mr. Amador, he was selling the H&K SP89 with the accessories that he collected for it, which included a vertical front grip and a shoulder stock. If Mr. Amador merely possessed the vertical grip, the pistol would have to be registered under the NFA as an AOW. However, because he also had a stock, the pistol would have to be registered as a short-barreled rifle, PRIOR to purchasing or possessing the shoulder stock and/or vertical grip.

This same logic applies to your short-barrel-shotgun. You have built a SBS prior to paying for the "right" to do so. (I know - disgusting). I would take the barrel out of the house and store it elsewhere while I found a LEGAL length barrel to install on the gun.