It is worth pointing out that in the Las Vegas shooting the investigation never concluded if he actually used the bump stocks. Some of the guns had them installed but with his amount of preparation and knowledge of firearms he could have just as easily modified them to be fully automatic. During the course of the investigation they specifically prohibited the ATF from inspecting any of the weapons for modifications and merely said that the use of the bump stocks was a possibility, not a fact. The bottom line is it isn’t known one way or another if he actually used them, he might have but the firing rate was more consistent than most bump firing.