The brief contains the lie that Machine Guns are unusually dangerous to the public safety. From 1934-1986, one could go out and buy a brand new machine gun at a reasonable price, as long as you passed a tough background check and paid a $200 tax. During that time (which Parker would return to) there was only one (1) crime committed with a lawfully possessed machine gun, and that was by a police officer.
I believe in the constitution, and reluctantly believe that private possession of firearms is probably a good thing overall [I live in DC and the notion of the nutcases who work here walking around with guns is scary, but I concede the point on balance], but you gunnutters need to show some self restraint. Machine guns are unusually dangerous to the public safety as are 155mm Howitzers and nuclear bombs. When you overreach you scare folks who might otherwise be on your side.