The Las Vegas gunman was evil and possibly mental, to some degree, and he did have several, legally obtained, weapons along with some extras. This YouTube video is about some of the extras that are available and that surely he had. I'm a gun enthusiast, I have hunted, and I fully believe in the 2nd Amendment rights of Americans but I didn't know such accessories were available to turn a semi-automatic weapon into a, close to, automatic weapon.
https://youtu.be/_U6tORrODJE?t=16s
I'm not for eliminating these though because I fully believe that the 2nd Amendment covers such, at last as it was written. If the 2nd Amendment should be changed then it should be by the method prescribed in the Constitution to do so and not by legislation or executive order. At the time the Constitution was written the founders meant for the 2nd Amendment to cover military type weapons. The question for me is if they had known what innovations the future would bring to military type weapons would they have worded it differently. I don't know that they would because I believe the intent was to allow citizens to regain control of their government if it was taken over or got out of control.
I believe the real problem is the person behind the gun and not the instrument that the evil/crazy person chooses. He was a millionaire pilot with a plane and he could have just as easily loaded up the plane with fuel and/or explosives and flew into the crowd or into a motel there. More people are killed each year by drunks in cars should be ban alcohol and/or cars? It's said Smoking kills more than that in a year so should we ban smoking? Somewhere they needs to be sanity and consideration that there are some sane people and insane people. I don't know that you can ever prevent these things from happening, I actually think you can't but I was surprised at some of the accessories that are available to the public for these guns. In the video the Bump/Slide stock is shown and also you can see a drum magazine allowing for a great number of ammo to be expended without reloading.