The Congressional Research Service in 2009 estimated there were 310 million firearms in the U.S., not including weapons owned by the military. Of these, 114 million were handguns, 110 million were rifles, and 86 million were shotguns. In that same year, the Census bureau stated the population of people in the U.S. at 306 million.
Accurate figures for civilian gun ownership are difficult to determine. While the number of guns in civilian hands has been on the increase, the percentage of Americans and American households who claim to own guns has been in long-term decline, according to the General Social Survey. It found that gun ownership by households has declined steadily from about half, in the late 1970s and early 1980s, down to 32% in 2015. The percentage of individual owners declined from 31% in 1985 to 22% in 2014. However, the Gallup organization has been performing similar polls for the same interval, and finds that household ownership of firearms was approximately the same in 2013 as it was in 1970 – 43%, and individual ownership numbers rose from 27% in 2000, to 29% in 2013.
Household firearms ownership hit a high in 1993–1994 when household gun ownership exceeded 50%, according to Gallup polls. In 2016, household firearm ownership still exceeded 35%, and there was a long-term trend of declining support for stricter gun control laws. Gallup polling has consistently shown two-thirds opposition to bans on handgun possession.
Gun ownership figures are generally estimated via polling, by such organizations as the General Social Survey (GSS), Harris Interactive, and Gallup. There are significant disparities in the results across polls by different organizations, calling into question their reliability. In Gallup's 1972 survey, 43% reported having a gun in their home, while GSS's 1973 survey resulted in 49% reporting a gun in the home; in 1993, Gallup's poll results were 51%, while GSS's 1994 poll showed 43%. In 2012, Gallup's survey showed 47% of Americans reporting having a gun in their home, while the GSS in 2012 reports 34%.
In 1997, estimates were approximately 44 million gun owners in the United States. These owners possessed approximately 192 million firearms, of which an estimated 65 million were handguns. A National Survey on Private Ownership and Use of Firearms (NSPOF), conducted in 1994, indicated that Americans owned 192 million guns: 36% rifles, 34% handguns, 26% shotguns, and 4% other types of long guns. Most firearm owners owned multiple firearms, with the NSPOF survey indicating 25% of adults owned firearms. In the U.S., 11% of households reported actively being involved in hunting, with the remaining firearm owners having guns for self-protection and other reasons. Throughout the 1970s and much of the 1980s, the rate of gun ownership in the home ranged from 45–50%. Rapid increases in gun purchases characterized by exceptionally large crowds accruing at gun vendors and gun shows is consistently observed due to the possibility of increased gun control following highly publicized mass murders.
Gun ownership also varied across geographic regions, ranging from 25% rates of ownership in the Northeastern United States to 60% rates of ownership in the East South Central States. A Gallup poll (2004) indicated that 49% of men reported gun ownership, compared to 33% of women, and 44% of whites owned a gun, compared to only 24% of nonwhites. More than half of those living in rural areas (56%) owned a gun, compared with 40% of suburbanites and 29% of those in urban areas. More than half (53%) of Republicans owned guns, compared with 36% of political independents and 31% of Democrats. One criticism of the GSS survey and other proxy measures of gun ownership, is that they do not provide adequate macro-level detail to allow conclusions on the relationship between overall firearm ownership and gun violence. Kleck compared various survey and proxy measures and found no correlation between overall firearm ownership and gun violence. In contrast, studies by David Hemenway and his colleagues, which used GSS data and the fraction of suicides committed with a gun as a proxy for gun ownership rates, found a strong positive association between gun ownership and homicide in the United States. Similarly, a 2006 study by Philip J. Cook and Jens Ludwig, which also used the percent of suicides committed with a gun as a proxy, found that gun prevalence increased homicide rates. This study also found that the elasticity of this effect was between +0.1 and +0.3.
The effectiveness and safety of guns used for personal defense is debated. Studies place the instances of guns used in personal defense as low as 65,000 times per year, and as high as 2.5 million times per year. Under President Clinton, the Department of Justice conducted a survey in 1994 that placed the usage rate of guns used in personal defense at 1.5 million times per year, but noted this was likely to be an overestimate.
Between 1987 and 1990, McDowall et al. found that guns were used in defense during a crime incident 64,615 times annually (258,460 times total over the whole period). This equated to two times out of 1,000 criminal incidents (0.2%) that occurred in this period, including criminal incidents where no guns were involved at all. For violent crimes, assault, robbery, and rape, guns were used 0.83% of the time in self-defense. Of the times that guns were used in self-defense, 71% of the crimes were committed by strangers, with the rest of the incidents evenly divided between offenders that were acquaintances or persons well known to the victim. In 28% of incidents where a gun was used for self-defense, victims fired the gun at the offender. In 20% of the self-defense incidents, the guns were used by police officers. During this same period, 1987 to 1990, there were 46,319 gun homicides, and the National Crime Victimization Survey estimated that 2,628,532 nonfatal crimes involving guns occurred.
McDowall's study for the American Journal of Public Health contrasted with a 1995 study by Kleck and Gertz, who found that 2.45 million crimes were thwarted each year in the U.S. using guns, and in most cases, the potential victim never fired a shot. The results of the Kleck studies have been cited many times in scholarly and popular media. The methodology of the Kleck and Gertz study has been criticized by some researchers.