Well, even here on this site, there are some who have a problem with understanding that "SHALL NOT BE INFRINGED" means EXACTLY that.
We can no more legally (or more importantly *morally*) restrict the firearms that a free man owns (or carries) than we can restrict what religion a person chooses to worship. We can put limitations on where the person can discharge the weapon, just like we can restrict certain practices of a religion if they are harming someone else, but the ownership and carrying of the weapon are protected by the 2nd Amendment for all free men.