Thankfully, he, nor the others who have committed such crimes have chosen to use explosive properly. If the ones who did build explosives would of used them grenade fashion, things would of been phenomenally worse. And if they had taken terrorist actions in the use of explosives, it would be even worse than that. Most people just do not understand that a gun is a very inefficient way to kill large numbers of people. More efficient than a knife, sword or axe, but still grossly inefficient.