This action is less about whether bump stocks can be banned or not, it is about a failure in the method which was attempted to regulate them without a proper legislative process. Since the AFT had previously said that based on the definitions of what the device is, and more specifically what it is NOT (it doesn't make a semi-automatic rifle into an automatic rifle); therefore, the AFT could not regulate them under the Gun Control Act of 1968. Without the congress doing the job they are supposed to do, I don't see this going anywhere.
The NRA is already on the record for saying that devices which allow for semi-automatic rifles to "act like" automatic rifles are probably worthy of additional regulations. I'm sure the NRA doesn't see "bump stocks" as the high water mark for gun rights, and in my personal view on this issue I tend to agree. First off, the device is more of a novelty / toy than anything else anyway. It serves no purpose that I can think of in any real world tactical situation--- as they are very inefficient. These devices cannot even be defended as being a function of the rifle as it was designed to be. They are NOT in the same category as semi-automatic fire, removable box magazines, or STANDARD capacity magazines (10+)------ or any normal function of the weapon system. Basically, they may be fun, but they are not practical, so how can they be defended as such? If the issue ever gets to the SCOTUS I'm sure they will be deemed worthy of regulation--- exactly as the Heller decision hinted could happen. Not for these specifically, but for weapons available to, and intended for civilians, like the AR-15, the Mini14, and all other semi automatic standard capacity pistols. All acceptable and worthy to be used by civilians for civilian purposes under our 2nd Amendment protections. This device does not in my opinion rise to that level of legal protection. It is NOT a function of the rifle as designed.