U.S. Sen. Richard Blumenthal said Tuesday that in the aftermath of the school shooting in Newtown he will introduce a bill to require background checks on people buying gun ammunition.

The government has a background-check system for gun purchases but not for ammunition, even though it is illegal to sell both firearms and ammunition to felons, fugitives, drug addicts, the mentally ill and perpetrators of domestic violence.

Ammunition is the “black hole of gun violence prevention,” said Blumenthal, D-Conn., because under current law there is virtually no way to enforce the prohibition.

“A felon who walks into a store to buy ammunition can load an entire shopping cart, pay and walk out, no questions asked, because there are no background checks,” he said in a press conference call.

Blumenthal said that after the Dec. 14 shooting at Sandy Hook Elementary School, he spoke with many people in Newtown and throughout the state about gun violence and devised a set of proposals to introduce in the coming weeks.

The other bills will focus on banning assault weapons and high-capacity magazines, closing a loophole that allows the private sale of guns without background checks, and addressing the relationship between mental health issues and gun violence, Blumenthal said.

In addition to requiring ammunition buyers to undergo an instant background check in the FBI’s national database, the Ammunition Background Check Act of 2013 would require sellers of ammunition to notify law enforcement officials when someone buys more than 1,000 rounds of ammunition at once or within five days, or when a large quantity of ammunition is stolen.

Teflon-coated bullets and incendiary ammunition would be banned by the bill.

Several members of the new Congress have introduced measures to combat gun violence.

Blumenthal was asked during the conference call whether it would make more sense to wait for the administration to come up with a plan and make one concerted push. Blumenthal said his bill does not preclude a unified effort and it could be included as part of a larger initiative.

The system for background checks is in place and most background checks can be done in about 30 seconds, he said.

“I’m incredibly hopeful that a common sense enforcement tool like this one will have traction and success,” Blumenthal said. “And maybe, most importantly, I regard it as keeping faith with the people in Newtown and across Connecticut, people who were directly affected by this horrific tragedy.”

j.mcdermott@theday.com