according to at least one report they found ammonium nitrate in his trunk. What if he actually made bombs and used them in conjunction with a plane?
My point is a gun is just a tool. Right now it may be the easiest tool available, but someone hell-bent on killing as many people as possible will find another tool (which may be more or less effective depending on the individual's resources, resourcefulness and capabilities)
This can be argued both ways. On the one hand, yes, if an individual is hell-bent on committing mass murder, he will find a way. On the other hand, the vast majority of psychopaths will ONLY commit mass murder if it's not too complicated to carry out.
Driving a truck or a plane into a crowd requires a certain type of psychosis. It requires being up close and personal with your victims. You need to be a hardcore religious or political fanatic. A random disgruntled angry 64 year old will likely not do this.
The fact is, high powered rifles are the easiest way to commit murder on a large scale. It was too easy. The people at this concert were described as "fish in a bowl". He can shoot at them while perched comfortably in his 32nd floor hotel room and it's almost impossible for anyone to shoot back. (without a sniper rifle and professional sniper training). He doesn't even have to make eye contact with his victims.
There is a legitimate argument to make here that if he were unable to acquire the weapons and ammo legally, he would not go out of his way to acquire them on the black market. (The fact that he had a partially constructed bomb in his car kind of supports the argument that it was just too much work to do and shooting was much easier.) At the end, he may have just taken some pills or simply smash and jump out of the window.
I'm not anti-gun, but if a solution for further gun control was proposed, I would be willing to at least consider it.