(The Center Square) – A pro-gun group is filing for a temporary restraining order to stop a new law from going into effect that will raise the minimum age for firearm purchases to 21 in Colorado.

The age limit regulation, signed into law by Governor Jared Polis April 28, is set to take effect on Monday. On the same day the bill was signed into law, the Rocky Mountain Gun Owners, an affiliate of the National Association for Gun Rights, filed a lawsuit to stop the law, arguing it violates the Second Amendment of the U.S. Constitution.

“I don't think our members realized how serious I was when I told them I would sue immediately,” Taylor Rhodes, executive director of RMGO, said Thursday. “Before the ink was even dry on the paper, we had a lawsuit filed.”

A judge hasn’t ruled on an injunction filed by the organization in June to stop the law, so Rhodes prepared his legal team this week to pursue a temporary restraining order against the state.

“We didn't think we would have to use that, but it’s a tool in our tool belt and we feel like it is necessary to use in this case,” Rhodes said.

Senate Bill 23-169 was one of four bills Polis signed into law April 28. Illegal possession of a firearm by a person under 21 will be a class 2 misdemeanor and a class 5 felony for second and subsequent violations. There are many exceptions, including someone with a firearm attending a hunter’s education or firearms safety course and members of the U.S. armed forces and peace officers under 21.

“Young people aged 12-24 make up one-fifth of the population, but commit just under half of all gun murders,” Sen. Jessie Danielson, D-Wheat Ridge, and one of the bill’s sponsors, said in a statement. “… Raising the age to purchase a firearm will keep more deadly weapons away from our youth, reduce youth suicide rates, and make our communities safer.”

Rhodes criticized the legislature’s characterization of youth and firearms and their failure to address family stability and mental health issues in the state.

“It was always about disarming citizens and the more people they can disarm, the better,” Rhodes said. “We’re in an uphill fight. I hope and pray there is some type of common ground that is common sense.”

The other three bills Polis signed into law created a three-day waiting period for firearm purchases, repealed a Colorado law limiting liability for firearm and ammunition manufacturers, and expanded who can petition for an extreme risk protection order.

“They’re saying all guns are bad and let's just get rid of them,” Rhodes said. “That's not a smart way to go about it. Guns aren't going away. As long as Rocky Mountain Gun Owners exist, we're going to fight to make sure that they don't.”