This chart was updated on June 14, 2016, with new data from the Law Center to Prevent Gun Violence
— License/Permit: 13 states require people to obtain either licenses to own or permits to purchase a gun. These laws vary from state to state in other ways, for example in how long those licenses or permits are valid.
— Waiting Periods: While some states impose waiting periods on the sales of all guns, others only do so for certain types of guns. These waiting periods vary widely, from one day in Illinois for long guns to 14 days in Hawaii.
— Universal Background Checks: Eight states require background checks, whether the gun comes from licensed dealers or at gun shows or via other private sales. Others have restrictions, requiring checks only for handguns or using the permitting process to regulate sales — for example, requiring a background check before getting a permit.
— Registration: Registration laws vary widely from state to state. Some state laws require the registration of all or some firearms, while others expressly prohibit registries.
— Concealed Carry: In some states, the concealed carry law says that licensing officials "may issue" concealed carry permits. This is the strictest sort of law, giving officials the broadest authority in deciding who gets permits. Applicants may have to show, for example, that they have "good cause" or are of "good moral character." In others, the law says that states "shall issue" permits. In those places, officials have either no discretion or limited discretion. Still other states require no permit.
— Open Carry: Five states plus D.C. ban the open carrying of handguns, and four (again, plus D.C.) ban it for long guns. Others have other restrictions, such as requiring openly carried weapons to be unloaded, or they require permits.
— Assault Weapons: Seven states and the District of Columbia ban assault weapons. Minnesota and Virginia have no bans, but they have restrictions governing the possession of assault rifles.
— Domestic Violence Laws: There's already a federal law keeping people convicted of misdemeanor domestic violence crimes from buying or possessing guns. However, 16 states have laws that go above and beyond that, for example by expanding the definition of "domestic violence." Four others don't allow people convicted of crimes like assault or battery to buy or possess guns.