Yes, it is highly illegal to buy a sawed off shotgun. Just don't do it. The ATF will catch you and put your butt in jail.
Two undercover federal agents met with Sauke last January and bought a gun he had made. Sauke also showed them an illegal sawed-off shotgun. “Sauke’s actions and statements leading up to his arrest were very concerning, which is why law enforcement quickly intervened,” said ATF Special A...