Did you know that you can do simulated full-auto firing and it is absolutely legal? Bump Fire Systems has come up with Bump Fire Stock, which allows you to recreate the feeling of automatic firing. You can use it with your semiautomatic weapon by gripping the fore-end of the barrel and pulling it forward. Bump Fire uses a gun’s recoil to shoot multiple rounds. According to the company, Bump Fire Stock is legal because it cannot initiate an automatic firing cycle that continues until either the finger is released or the ammunition is gone. Firearms Technology Branch finds that the product is not a machine gun as defined under the Gun Control Act, 18 U.S.C.921(a)(23) and has complete ATF approval.
Check it out.