Connecticut gun owners are rushing to register certain firearms and ammunition that will be considered illegal contraband in the new year.

People have been lining up early in the morning at the state Department of Emergency Services and Public Protection's headquarters in Middletown in recent days to turn in applications for assault weapons certificates and high-capacity magazine declaration forms so they can legally keep the items.

Under a wide-ranging gun control law, passed earlier this year in the wake of the Sandy Hook Elementary School mass shooting in Newtown, gun owners have until Tuesday to submit the paperwork.

Michael Lawlor, Gov. Dannel P. Malloy's undersecretary for criminal justice, predicted a flood of registrations over the final days of 2013.

"It sounds like a lot of these folks were holding off on doing it in anticipation of a potential decision or something," Lawlor said, referring to pending legal challenges to the state law, which expanded the definition of assault weapons in Connecticut to include more banned weapons. The law also bans the sale or purchase of magazines that hold more than 10 rounds of ammunition. Like the newly defined assault weapons, existing magazines can be kept so long as they're registered with the state.

"One thing is clear," Lawlor said. "If you haven't registered it, on the following day, it is completely illegal contraband" starting on Jan. 1.

The Connecticut Citizens Defense League, which is participating in a legal challenge of the new law, has been working to remind gun owners that the deadline to register and declare the assault weapons and high-capacity magazines is approaching quickly.

"Many people are still not aware of the law itself, or the actual date of implementation," President Scott Wilson said. "While CCDL wholeheartedly believes that this law is unconstitutional, we want to make sure that law-abiding gun owners do not become felons on Jan. 1."

Wilson said his organization is particularly concerned that people may not be aware they're affected by the law because many handgun magazines and semi-automatic rifle magazines with a capacity to hold more than 10 rounds of ammunition were sold standard along with guns before April 4, the last day people could legally purchase or sell those weapons and magazines in Connecticut. There are exceptions for members of the military, law enforcement and others.

Wilson has estimated there may be as many as 20,000 weapons in Connecticut affected by the new law.

Lt. J. Paul Vance, a spokesman for the Connecticut State Police, said the agency is trying to make the process as smooth as possible for those looking to register their weapons and magazines. For example, notaries have been stationed at the DESPP headquarters to assist applicants. To obtain an assault weapon certificate, gun owners need to submit proof such as a valid sales receipt that they purchased the weapon before April 4. They also can submit a sworn affidavit that must be notarized.

The application requires information such as the individual's name, address, telephone number, motor vehicle operator's license, sex, height, weight and thumbprint, as well as information about the weapon, including the serial number, model and any unique markings.

The large-capacity magazine declaration form includes much of the same information, including the applicant's address and driver's license number.

Get the Monitor Stories you care about delivered to your inbox. By signing up, you agree to our Privacy Policy

Under the new law, the registered large-capacity magazines can be kept fully filled at the owner's home. They can also be taken to a licensed shooting range or gun club and filled to capacity there. Ultimately, advocates hope the law will prompt people to turn in the magazines.

"I think over time, there's just going to be fewer and fewer of those in circulation," Lawlor said.