The sustained rate of fire of semi automatic AR-10, AR-15 is 12-15 rounds per minute. If someone were to use these like the alleged single shooter in Vegas did, they would lose a tremendous amount of accuracy and ruin their weapons rather quickly. If they are well funded like this alleged shooter allegedly was, they will just buy the devices on the black market anyways. The result is the same. Law abiding individuals will loose the ability to own these and be at the mercy of crazies and criminals who don’t care about the law.