From CBS News Website.
As America reels from yet another mass shooting, inevitable questions resurface about guns laws and the nation's pervasive firearm culture. Here is a look at per capita weapons data, based on the ATF's National Firearms Registration and Transfer Record, and 2013 data from the U.S. Census.
While the ATF's National Firearms Registration and Transfer Record is the only accessible list of its kind, it is not all-inclusive. NFA firearms only include the categories regulated by The National Firearms Act of 1934: machine guns, short-barreled rifles, short-barreled shotguns, suppressors, destructive devices like bombs and grenades, concealable devices with the ability to discharge a shot through the energy of an explosive, and any firearm with a bore over half an inch that has not been determined to have a legitimate sporting use.