But lots of gun crime occurs when it's the case of an illegal weapon too.
Is a gun ban really practical and how will it be policed and enforced?
This is a very good point.
If you want to eliminate mass rampage shootings in the US like the recent Oregon attack, yes, a gun ban could and likely would drastically reduce their occurrence since many times the rampage shooter seems to acquire his weapons in the days or months leading up to the attack.
However, this would not end gun violence across the board and won't necessarily end rampage killings as a simple google search can show you how to make black powder from common household and hardware store items. The powder can then be made into an IED. America has a problem with crazy people, and crazy people will find a way.
There are over 300 million guns (and thats a very conservative estimate) owned by private citizens in the U.S. Only a small percentage of them are registered. It would be virtually impossible to collect them all and confiscate them all. At best, only upstanding law-abiding citizens would turn them in. The criminal element, of which a vast majority of gun deaths are attributed to, would have no reason to turn in their arms. And the extreme whack-job anti-government white supremacists wouldn't likely turn theirs in either.
300 million+ guns, 11,000+ gun deaths in 2013. If a separate gun was used for each death, only 0.004% of private citizen's guns were used. In other words, 99.996% of guns owned by Americans were not used to kill anyone.
Gun crimes, especially mass killings, get a lot of press and cause a lot of emotions. And the victims of those crimes deserve justice.
But the stats just don't back up the claim that the cause and reason those crimes were committed was because of a gun culture. If that were true, the number of deaths would be a lot higher.