Handgun purchase laws vary by state and municipality, but federal law allows all individuals age 21 or older, who do not fall into certain categories, to buy a handgun, says About.com. Federal barriers to handgun purchase include certain criminal convictions, controlled substance abuse and dishonorable military discharge.
Federal law prohibits handgun purchase by individuals previously convicted of crimes punishable by more than a year in prison, who are under indictment for such crimes, who have been convicted of any domestic violence offense, have current restraining orders against them by partners or partners' children or have renounced U.S. citizenship, as well as by those who have illegal alien status, are fugitives from the law, or have been declared mentally defective or committed to a mental institution, says About.com. The Washington Post reports that in 1992 Congress authorized restoration of gun rights to those once involuntarily committed that state programs later deemed mentally fit, but it did not assist or require states to institute such programs.
The Law Center to Prevent Gun Violence lists six states that require a permit to purchase handguns specifically, one state that requires a license to own handguns and seven states that require a permit to purchase or license to own all firearms. Several of these states also require safety training or examination. Federal law requires federally licensed dealers to perform background checks; several states also require background checks for handgun sales or all firearm sales.