Vermont lawmakers are ready to vote on a massive gun-control bill on Friday, as gun-rights activists are rallying against politicians who oppose their Second Amendment rights.

On Friday, the Vermont House of Representatives will debate a bill with wide-ranging gun controls, including one provision that is likely to provoke a constitutional challenge in federal court.

While Vermont may be liberal on most issues, from economic to social, they also tend to be staunch supporters of the right to keep and bear arms. It is one of the only states where citizens can carry concealed handguns with no permits whatsoever, and gun rights are often supported by Democrats as well as Republicans.

At least 42 percent of Vermont households own firearms (the actual number may be as high as 70 percent), and it boasts a record as one of the lowest-violence states in the nation.

Politicians were not pushing gun control in the state capital of Montpelier after the Parkland shooting in Florida. But after a disturbed 18-year-old threatened to shoot students at Fair Haven Union High School in a plot he penned in his chillingly titled Diary of an Active Shooter, Vermont Gov. Phil Scott – a Republican – said he “changed completely” on Second Amendment rights.

Several gun-control bills were filed between the state’s House and Senate after Scott’s flip-flop.

Ironically, a bill written to help gun owners, S. 55, became the vehicle for an anti-gun agenda. It was filed by a Second Amendment supporter to require the government to sell its backlog of firearms seized in law enforcement activities to licensed gun dealers, to offload 1,100 guns that had piled up in state facilities.

But in the House, the bill then became a Christmas tree for gun-control activists. It bans firearms that can carry more than ten rounds of ammunition at a time. Common models of handguns, such as double-stack magazine Glocks and Sig Sauers, would become illegal. A law-abiding gun owner carrying a common, legal handgun in New Hampshire who works in Vermont could become a criminal simply by crossing state lines as he drives his daily commute.

The bill would also require gun owners to securely lock up every firearm when not in their immediate possession. A person walking across the street to talk to a neighbor would break the law unless he first locked up every firearm in his house before leaving the front door.

S. 55 also requires every gun owner to go through a background check system to sell any gun he owns unless the buyer is an immediate family member. A woman would commit a crime if she sells a handgun to her elderly aunt or to her best friend without first going to a licensed gun dealer and paying money for a background check to be performed.

Another provision likely violates the Second Amendment to the U.S. Constitution. S. 55 raises the minimum age to purchase any firearm to 21. Under federal law, a person need only be age 18 to buy a gun.

But more importantly, 18 is the age at which Second Amendment rights extend to a U.S. citizen. Should S. 55 become law, a law-abiding citizen age 18, 19, or 20 could file a federal lawsuit against the state.

The National Rifle Association (NRA) has already filed such a lawsuit against Florida, which just changed the purchase age to 21. The NRA is represented by Supreme Court heavy-hitters Chuck Cooper and David Thompson, in a case that could go to the nation’s highest court.

Gun owners have weighed in against S. 55. But representatives from the NRA’s state affiliate, the Vermont Federation of Sportsmen Clubs, tell Breitbart News that some of their emails to lawmakers have actually been diverted to spam folders, and lawmakers are not being given written messages from many of their constituents who are calling to oppose the bill.

“The Federation has long held that laws should be based on sound public policy and in compliance with the state and federal constitutions,” says President Evan Hughes in an exclusive interview with Breitbart News. “The amendments to S. 55 in no way meet these important standards.”

Gun-rights supporters are particularly outraged that House Speaker Mitzi Johnson refused to allow a single public hearing on S. 55, insisting that Vermont gun owners would be incensed if they knew how many ordinary firearms would be banned under this legislation.

Ironically, in pushing S. 55, lawmakers have let sit S. 221, a bill supported by gun-rights advocates to identify dangerous people.

S. 221 was originally intended to establishment ERPOs – emergency risk protection orders. Most people have committed no crime and never been committed to a mental institution. However, there are some such people regarding whom family members can present evidence showing it is likely that the person has become a danger to himself or to others. The ERPO would allow that person to be temporarily disarmed while the authorities investigate further.

The NRA endorses ERPO laws that include robust due-process protections to secure the rights of law-abiding and peaceable gun owners, and the Vermont Federation endorsed S. 221 as one such bill. S. 221 passed the Senate 30-0, and would be expected to pass the House unanimously if lawmakers would put that legislation forward.

But instead of S. 221, lawmakers will debate the S. 55 gun-control bill this week. Second Amendment supporters are hoping that raising public awareness on these unprecedented restrictions on law-abiding gun owners will derail those efforts.

Ken Klukowski is senior legal editor for Breitbart News. Follow him on Twitter @kenklukowski.