Let's go ahead and make murder "super triple" illegal. That'll be sure to stop it.
Making guns illegal will lead to:
1. A huge underground, black market for guns, and all the elements that come with an underground black market (mafia, violence, etc.)
2. Crude, home-made guns popping up every where. Believe it or not a gun is not THAT sophisticated of a machine. We aren't talking a nuclear reactor here. Anyone with some basic equipment and training will be able to make a functioning firearm.
Do you really think someone who wants to murder as many people as possible gives a flying rat's behind about breaking a "gun" law?
Has making drugs illegal stopped people from buying/selling drugs?
A gun is simply an inanimate lump of metal and/or wood.
People who want to kill others can/will always find a way.
ZERO guns involved ^^^^