A startling new survey reveals that just 3% of Americans have 50% of all the citizen-owned firearms in the nation.

Some of these "super owners" have as many as 140 guns.

Americans own an estimated 265 million guns; that's more than one firearm for every adult, according to an unpublished Harvard/Northeastern University study obtained by the Guardian.

The survey estimates that 133 million of these guns are concentrated in the hand of the super owners.

The number of guns in America has increased by 70 million since 1994. But the percentage of American gun owners has decreased slightly from 25% to 22%.

The number of gun-owning women is up slightly while the number of gun-owning men has dipped a bit. Women were more likely than men to own a gun for self-defence, and more likely to have only a handgun.

Handguns in general are making up more and more of all the firearms in the nation's gun stock, and experts believe this indicates that Americans are turning to guns primarily because of fear, and are seeking a firearm primarily for protection.

9mm Gun
Lost of Americans love their guns.Getty Images

"If we hope to reduce firearm suicide, if we hope to reduce the other potential dangers of guns, my gut is, we have to speak to that fear," Dr Deborah Azrael, a Harvard School of Public Health firearms researcher and the lead author of the study, told the Guardian.

Roughly 20,000 of America's more than 30,000 annual gun deaths are suicides.

Among the estimated 55 million American gun owners, most own an average of just three firearms. Nearly half own just one or two, according to the survey.

America's estimated 7.7 million super gun owners have between 8 and 140 firearms.

Azrael said there is no research on "whether owning a large number of guns is a greater risk factor" than owning a few guns.

"We know almost nothing about that," she said.