Ask gun manufacturers to stop the production of assault rifles and high capacity magazines

I've heard many people say that if we ban assault weapons/rifles and high magazine bullets that all that will do is arm criminals and that the average citizen will be put in harm's way and not able to defend themselves against such criminals. I say eliminate the supply and confiscate the ones that already exist. What's the point in having them in the first place except to kill? No human being should have that much power to create that much carnage.