Who is selling

for at least some

About a third

databases, while others also

Some states refer only to federal

whether the purchaser is eligible.

NICS, the system consults three

When dealers initiate a check with

in gun sales from

sale, even at gun shows.

System (NICS) before making any

check through the F.B.I.’s National

and he had to switch to a

the one above until it jammed

others in July 2012 used a

The gunman in the Aurora,

state has no limits on

one above. The weapon was

a 30-round magazine like the

had a semiautomatic rifle with

The gunman in the December

to kill 33 people, the deadliest

used two handguns with

proposal. In the 2007 Virginia

be permissible in Mr. Obama’s

This 10-round magazine would

Mr. Obama proposed requiring background checks for all gun purchases. The checks are

intended to determine if someone has a a criminal, drug, mental health, domestic violence or

other type of record that disqualifies them from buying the gun. Current federal law does

not require them in private sales. In 2009, about 1.4 percent of applications for firearm

purchases or permits were denied.