The best method to eliminate crime would be to eliminate all free will, all ambition, all emotion.
Until that happens, banning guns is an ineffective approach to the problem.
I ask you- how would you deny all would-be mass shooters a gun?
Firearms are a relatively simplistic technology. You cannot un-invent them, nor will you ever succeed in finding and destroying any significant portion of the world's current unregistered firearms. Thus, the classic argument:
What is accomplished by creating laws requiring the disarming of the populace in the hope criminals will obey them?
On another note..
Iff you can somehow eliminate firearms-
Do you think people who are willing to put days, weeks, even months, into planning an assault will be balked by having difficulty getting firearms?
Ever heard of timothy mcveigh?