The lawsuit points to the shooting in Sutherland Springs, Texas, as an example of failure to report a person who's barred from buying guns.
Schools themselves might have taken a more active role than Congress in preventing future massacres.
A measure to make all concealed carry permits valid nationwide and strengthen background checks passed the House on Wednesday.
Republicans in the House argue concealed carry permits should be honored nationwide, just like U.S. driver's licenses, but others aren't so sure.
A report found that 74 percent of the traceable guns recovered from New York crime scenes didn't originate in the Empire State.
Congress approved more than $1 billion to help states improve their records communication systems to get more data into the NICS.
Dwyane Wade has lashed out against his hometown of Chicago's gun laws, calling them weak.
Relatives of victims and survivors of the shooting are reportedly seeking actual and compensatory damages.
The new laws put restrictions on purchasing assault weapons and further regulate the sale of ammunition.
A "buy one, donate one" campaign for guns is actually an elaborate hoax.
Rep. John Lewis is leading his colleagues in the sit-in, which began Wednesday on the House floor.
The Supreme Court declined to rule on a case that could have larger implications in the national discussion about guns with large magazine capacities.