The gun control act of 19 68 just passed by the congress and signed in the law by the president, grants possessors of certain types of firearms 30 days of grace in order to register these weapons. So some of these firearms are machine guns, short barrelled rifles or shot guns, suppressors,. There's no such as a silencer because it doesn't make it silent. It just suppresses the sound. But these types of guns you very rarely see used in crime or violence in the us. Because there are so many safeguards and structures put around the acquisition of these that they just don't often fall into the wrong hands.