Legislators have introduced more than 1,300 bills to change state gun laws, according to records kept by the Law Center to Prevent Gun Violence, a San Francisco-based group tracking gun legislation.
Here's a quick review of some of the more notable proposals under consideration in states where gun laws are moving fast, based on state-level news reports and conversations with experts tracking the debate. We'll do our best to update the list as events warrant:
Updated April 8, 12:04 p.m. ET
Arkansas: The state lifted restrictions on carrying firearms on college campuses and places of worship. Guns are permitted at places of worship and affiliated schools if the organization has already approved guns on the premises. A bill permitting guns in bars and liquor stores is working its way through the state legislature, while the state House Judiciary Committee tried but failed to approve a proposal last week that would nullify federal gun laws on certain firearms.
California: Legislators are considering what supporters call the LIFE Act, which includes 10 proposals that would stiffen the state's already-aggressive gun laws and make the Golden State the least gun-friendly state in the nation.
One proposal would strengthen the state's assault weapons bans by banning any semi-automatic rifle that accepts detachable magazines. Other proposals include an expansion of the state's firearm record-keeping system, a ban on the sale and possession of ammunition magazines holding more than 10 rounds, a ban on bulk purchases of ammunition, and a requirement that people obtain a permit to purchase ammunition.
Bottom line: California already has the strictest gun laws in the nation. If passed, these proposals would make the state's laws even stricter.
Colorado: Legislators approved a new universal background check system and agreed to limit the size of ammunition magazines to just 15 rounds -- a limit above the 10-round limit under consideration in Congress and in several other states. The new law also requires gun owners to pay for the cost of processing a background check and requires state officials to provide information on domestic violence cases and restraining orders to the National Instant Criminal Background Check System (NICS). Finally, provisions of the law permit law enforcement to seize the weapons of people convicted of certain domestic violence crimes.
Approval of new gun laws in this purple state raised eyebrows nationwide, but the state's history with mass shootings -- at Columbine High School and the Aurora movie theater -- compelled lawmakers to act. Passage of the law was a major victory for Gov. John Hickenlooper (D), who is one of several Democratic governors pushing new gun laws while also weighing future national ambitions.
Connecticut: The Nutmeg State's gun laws are now some of the strictest in the nation, as state lawmakers approved a series of changes, including new restrictions on weapons and large capacity ammunition magazines.
The state's assault weapons ban -- already one of the most aggressive nationwide -- is being updated to include 100 newer weapons and related parts. It is a more comprehensive ban than most because it lists specific makes and models and only requires a weapon to have one specifically-banned characteristic. Owners of the banned weapons may keep them, but must register with the state.
The law also requires people convicted of certain gun crimes to register with the state, a program similar to the registration of sex offenders. These provisions mirror a similar law passed in New York City in 2006.
Delaware: The First State is considering several proposals introduced in recent weeks by Gov. Jack Markell (D), who is also chairman of the National Governors Association and said to be angling for an eventual political promotion.
The state House has approved a bill requiring background checks on almost all private and commercial firearms sales, permitting exceptions for exchanges between close family members or by law enforcement, or people who already have a concealed carry permit. In a nod to gun-rights activists, the bill explicitly prohibits the state from establishing a gun registry with information compiled by licensed dealers conducting background checks.
Legislators may also consider a bill making it a felony to carry firearms in designated "safe school" zones, a definition that includes schools, school buses and school property, but not cars parked on school property. There's also a proposed assault weapons ban that would require the owners of any of the banned weapons to register them with the state police within four months of the law's passage. Finally, legislators may consider a bill requiring gun owners to report lost or stolen weapons within 48 hours of realizing it's missing. Failing to report a missing weapon would result in a misdemeanor charge on the first offense and a low-grade felony any time after.
Kentucky: State legislators recently voted to lift a six-month residency requirement before people can apply for a concealed carry permit.
Maine: State lawmakers are debating legislation that would keep information about concealed-weapon permit holders off the public record. A legislative committee has approved the bill, but added an amendment that would allow the release of statistics on concealed-carry permits, including the number of permits applied for, issued, revoked or suspended and the gender, place of residence and age ranges of applicants.
Maryland: State lawmakers gave final approval in early April to a measure that requires the fingerprinting of gun buyers, limits firearm purchases by the mentally ill, and bans assault weapons and magazines that hold more than 10 rounds of ammunition. The law, which is scheduled to go into effect Oct. 1, will give Maryland some of the nation’s most restrictive gun measures and deliver a political victory for Democratic Gov. Martin O’Malley as he ponders a potential 2016 presidential run.
Massachusetts: The Bay State also has strict gun laws, but Democratic lawmakers and Gov. Deval Patrick (D) are pushing for a law that would limit the size of ammunition magazines to just seven rounds -- similar to a new New York law (see below). Supporters also want additional controls on the number of weapons a licensed dealer may sell to a person each year; a statewide electronic database on gun sales; and requirements that officials submit more information to the NICS.
Mississippi: Lawmakers in March approved two new bills that relax gun restrictions. The first measure clarified that anyone with a concealed carry permit will not be penalized if their gun is showing, so long as part of the weapon is covered. The second law exempts information on people with concealed carry permits from the public record, a bill that supporters said was prompted in part by a suburban New York newspaper's decision to publish information on people with permits.
Minnesota: A state House committee approved a bill that would close the "gun show loophole" by requiring background checks on purchases at gun shows. In the state Senate, Democrats approved a universal background check plan, but admit that it faces daunting odds.
The fight for stricter gun laws has proven difficult in Minnesota -- the original background check proposal in the state House would have exempted just exchanges between family members, but now it's likely to apply only to gun shows, if at all.
New Jersey: The Garden State already has strict gun laws: Buyers must obtain a permit or ID card after completing a background check and must agree to disclose mental health records. The state assembly has approved a bill requiring the state to submit mental health records to the NICS -- and the bill is expected to earn a vote soon in the State Senate.
New Mexico: Various legislative committees considered a bill to close the "gun show loophole" by requiring background checks at gun shows, but the bill wasn't given an up-or-down vote before the 60-day legislative session ended.
New York: In a victory for Gov. Andrew Cuomo (D) -- another governor thinking about running for president -- the Empire State moved faster than any other state to pass even stricter gun-control measures after the Newtown shooting. State legislators approved a bill in January that updated the state's assault weapons ban, established a statewide gun registry and restricts the size of ammunition clips to just seven rounds, less than the 10-round limit in other states. In response to industry pressure, legislators plan to amend the law to permit magazines that can hold 10 rounds, but the owner will be allowed to carry just seven rounds. The bill, which earned bipartisan support, also establishes a statewide firearm licensing standard.
The New York legislation also expanded and extended a law permitting judges to order residents to undergo psychiatric treatment if they meet certain criteria and expanded outpatient treatment of up to a year. In response to the December shooting deaths of two firefighters, the new law also established mandatory life sentences for anyone who murders certain first responders.
South Dakota: The state now permits school boards to establish "school sentinel" programs that "school sentinel" programs that will permit school employees, school security personnel or volunteers to carry firearms on school property. All eligible participants must pass a training program.
Tennessee: Lawmakers approved a bill in March permitting people with handgun carry permits to store firearms in their vehicle no matter where they are parked, with certain exceptions. Some opponents have questioned whether the law violates state employment laws regarding guns in certain places.
Utah: The state has passed a series of new laws related to gun violence. Lawmakers approved a bill permitting people to voluntarily surrender a weapon to law enforcement for up to 60 days to avoid incidences of gun violence. After years of debate, the legislature also passed a measure permitting anyone 18 or over who is in a dating relationship and has been the victim of violence or a threat to obtain a protective order. Previously only spouses or people living together could obtain such an order.
But in a defeat for gun rights supporters, Republican Gov. Gary Herbert vetoed a "Constitutional Carry" bill that would have allowed residents to carry a concealed gun without a permit.
Wyoming: State lawmakers approved a law clarifying that a judge may carry a firearm in his courtroom or determine that someone else may carry a weapon in his or her courtroom. A state district court judge sparked the controversy late last year, prompting legislators to act.
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Republican Gov. Gary Herbert last month vetoed legislation that would have allowed residents to carry a concealed gun without a permit.