Please,
All trump is doing is an executive order, which can be taken away with the next or following the next, president.
What he has done is a strategic move for all of the Republican Congress critters, who have legislation to ban the bump stocks but Ryan and McDonnell are too afraid to bring them to the floor for a vote, due to all the NRA pressure they have gotten on it and all the pressure their Republican Congress critters and senators have gotten on it with the NRA threatening to run a Republican against them in the primary...
What Trump's move has done, is protected all the Repubs in congress.....