A new state-issued eligibility certificate would be needed to purchase any rifle, shotgun or ammunition under the legislation. To get the certificate, a buyer would need to be fingerprinted, take a firearms training course and undergo a national criminal background check and involuntary commitment or voluntary admission check.
The deal is "the most comprehensive package in the country because of its breadth," said Senate Minority Leader John McKinney, a Fairfield Republican whose district includes Newtown.
McKinney said people tend to focus on assault weapons and high-capacity magazines, but he said "there's a lot here underneath the surface" addressing mental health and other issues.
The proposal was revealed to rank-and-file lawmakers Monday after weeks of negotiations among legislative leaders. A vote was expected later this week in the Legislature, where Democrats control both chambers, making passage all but assured. The bill would then be sent to Gov. Dannel P. Malloy, who has helped lead efforts to strengthen the state's gun laws.
Both Democratic and Republican leaders were expected to support the proposal. Connecticut is sending a message to Washington and the rest of the country "this is the way to get this job done," said House Speaker Brendan Sharkey, a Democrat from Hamden.
Legislative leaders have been negotiating since early March, reviewing recommendations on guns, mental health care and school security in the wake of the shooting.
Six relatives of Newtown victims visited the Capitol on Monday, asking lawmakers to include a ban on existing high-capacity magazines. Some handed out cards with photographs of their slain children. They delivered a letter signed by 24 relatives that demanded that legislators include existing large-capacity ammunition magazines in an expected ban on the sale of magazines that carry 10 or more bullets.
Allowing such large-capacity magazines to remain in the hands of gun owners would leave a gaping loophole in the law, said Mark Barden, whose 7-year-old son, Daniel, was killed in the shooting.
"It doesn't prevent someone from going out of the state to purchase them and then bring them back. There's no way to track when they were purchased, so they can say, 'I had this before,'" Barden said. "So it's a big loophole."
The gunman in the Newtown shooting blasted his way into Sandy Hook Elementary School and fired off 154 shots with a Bushmaster .223-caliber rifle within five minutes. He went through six 30-round magazines, though half were not completely empty, and police said he had three other 30-round magazines in addition to one in the rifle. He gunned down 26 people, then shot himself to death with a handgun.