First and foremost any ban on the purchasing of a firearm (which has, unfortunately already been done in the past) is a violation of the 2nd amendment and therefore in complete disregard of the United States Constitution.
Trying to ban firearms is a completely pointless gesture. If someone wants to shoot a bunch of people, then making it illegal to purchase the weapon, will simply make them obtain illegally.
There are more people killed in a week by means other than guns, then guns do in a year (ex. Knives, baseball bats, explosives, and medical malpractice). Yet there has been no outcry to stop these killings. The saying: "Guns don't kill people, people kill people" is a perfect example of this.