Gun owners have filed a second lawsuit against the state over gun-related provisions in a new school-safety law, this time alleging that a ban on "bump stocks" is an unconstitutional taking of property.

The case, filed last week in Leon County circuit court, asks a judge to certify a class action and order "full compensation" for what the plaintiffs' attorneys estimate are "tens of thousands, or more" Floridians who own bump stocks or similar devices.

The ban on bump stocks, which make semi-automatic weapons mimic fully automatic firearms, was included in a law passed this month in response to the Feb. 14 mass shooting at Marjory Stoneman Douglas High School in Parkland that left 14 students and three staff members dead and 17 injured.

The law also raised the minimum age from 18 to 21 and imposed a three-day waiting period for purchasing long guns, such as the AR-15 semiautomatic weapon 19-year-old Nikolas Cruz legally purchased and used during the deadly Valentine's Day shooting spree.

In the 17-page complaint in the bump stock case, lawyers for the plaintiffs argued that the Florida Constitution bars the state from taking private property "except for a public person and with full compensation therefore paid to each owner."

Because the new law deprives the plaintiffs and other members of the class of the "economically beneficial uses of their lawfully-owned property," the statute "constitutes a 'regulatory taking,' " argued lawyers Aaron Behar and Michael Harper, of the Behar Behar law firm in Sunrise and Puerto Rico-based lawyer Andrew Kagan.

The law "is so onerous that its effect is tantamount to a direct appropriation of property, and therefore, a compensable taking under the Fifth Amendment," the lawyers argued.

But Sen. Bill Galvano, a Bradenton Republican who sponsored the bill, signed into law by Gov. Rick Scott less than two weeks ago, said he stands by the prohibition.

"I have made a cursory review of the suit and continue to support the ban. At the end of the day, these devices turn semi-automatic rifles into machine guns. A policy decision consistent with the authority of the state has been made that this is not acceptable," Galvano, a lawyer who will take over as Senate president in November, told The News Service of Florida on Tuesday.

The lawsuit also refers to a 2010 directive issued by the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, that determined bump stocks are a "firearm part" and not regulated as a firearm under federal gun laws.

Plaintiffs and others relied on the ATF's determination when purchasing bump stocks and similar devices, such as binary triggers, the lawyers argued. The named plaintiffs in the case are identified as Florida residents Jonathan Hunt, Justin Brashear, Christopher Mays, Clayton Woolfe and Joseph Truex, who own bump stocks or binary triggers. The named defendants are Attorney General Pam Bondi and Florida Department of Law Enforcement Commissioner Rick Swearingen.

Marion Hammer, the National Rifle Association's Florida lobbyist, said recently that the gun-rights organization is expected to challenge the bump-stock ban after the portion of the law dealing with the devices goes into effect on Oct. 1.

Shortly after Scott signed the law, the NRA filed a federal lawsuit that challenges the Legislature's decision to require people to be age 21 before purchasing rifles and other types of long guns. The lawsuit accuses the state of violating the constitutional rights of young adults between the ages of 18 and 21.