The new law also immediately bans the sale of magazines capable of holding more than 10 rounds of ammunition. People who purchased those guns and magazines before midnight Wednesday will be allowed to keep them, so long as they're registered with the state police before Jan. 1. Required background checks for private gun sales also take effect.
Other parts of the new law that take effect over the coming year include a ban on armor-piercing bullets, establishment of a deadly weapon offender registry, expansion of circumstances when a person's mental health history disqualifies them from holding a gun permit, mandatory reporting of voluntary hospital commitments, doubled penalties for gun trafficking and other firearms violations, and $1 million to fund the statewide firearms trafficking task force.
Members of Malloy's administration met Thursday morning to discuss how to implement the legislation. Malloy said the affected state agencies plan to have everything in place by Aug. 1.
Connecticut lawmakers spent more than 13 hours debating the measure. Ultimately, the bill passed both chambers with bipartisan votes.
"I pray today's bill — the most far-reaching gun safety legislation in the country — will prevent other families from ever experiencing the dreadful loss that the 26 Sandy Hook families have felt," said House Majority Leader Joe Aresimowicz.
Some Connecticut lawmakers questioned whether the wide-ranging bill would have prevented 20-year-old Adam Lanza from blasting his way into his former elementary school.
"These laws will only be obeyed by people who choose to obey them. Criminals will still have their guns and their magazines and they will still commit their crimes," said Republican Rep. Robert Sampson. "Do we really think do we really think that adding more laws to our books would have stopped him?"
Associated Press writer Stephen Kalin contributed to this report. Follow Susan Haigh on Twitter at http://www.twitter.com/SusanHaighAP .