Just came across this chart posted in the Huffington Post. It makes me want to find out how they came up with the estimate of 270 million guns.  I would also want to know how many of these guns are actually registered and licensed. Is there an interest in inflating the number of guns owned in the US?

Mother Jones reported:  that there were an estimated 310 millon guns in circulation in the United States as of 2009, according to a survey from the National Institute of Justice. That number includes 114 million handguns, 110 million rifles, and 82 million shotguns. They also noted that 47 percent  of Americans reported having at least one gun in their home, according to a 2011 Gallup poll. Of those, a majority – 62 percent – admitted to owning multiple guns.