By Steve Gorman

LOS ANGELES California Governor Gavin Newsom on Tuesday signed into law a first-in-the-nation state excise tax on sales of firearms and ammunition, aimed at raising a projected $160 million annually to prevent gun violence in schools and elsewhere.

The California excise tax, due to go into effect in July 2024, will essentially add an 11% levy on top of the existing federal excise gun and ammo tax, a rate of 10 or 11%, depending on the type of weapon.

The measure, part of a package of gun safety bills signed by Newsom, was enacted four days after a federal judge struck down a California ban on high-capacity ammunition magazines, ruling that it unconstitutionally infringed on Second Amendment rights of gun owners.

Newsom's office said his action on gun safety also came in "the wake of shootings across the country that have left at least 104 people dead over the past 74 hours."

"While radical judges continue to strip away our ability to keep people safe, California will keep fighting - because gun safety laws work," Newsom, a Democrat, said in a statement.

Newsom said data showed the rate of gun-related deaths in California, home to some of the most stringent firearms laws in the U.S., is more than 40% lower than the national average.

The California excise tax would be collected on the gross receipts of manufacturers, retailers and dealers derived from gun and bullet sales in the state.

The tax measure was one of nearly two dozen gun safety bills passed during the latest session of the Democratic-controlled California legislature and signed by Newsom days after his administration vowed to appeal last week's federal court ruling on high-capacity magazines.

One prominent bill from Tuesday's package is aimed at toughening California's concealed gun permit law, raising from 18 to 21 the minimum age at which a gun owner can apply for such a permit, increasing advance training requirements and banning alcohol consumption while carrying a concealed weapon.

Sponsors said the measure, which also would bar concealed weapons altogether in airports, around schools and other sensitive zones, was crafted in such a way as to protect the measure from conservative legal challenges.

Still, the California Rifle & Pistol Association, a gun rights advocacy group, posted a statement on the social media platform X saying it had already filed a "preemptive lawsuit" against the measure.

Supporters of the new tax pointed to a 2021 report by gun control advocates that found gun deaths and injuries cost California $22.6 billion annually, of which $1.2 billion is paid directly by taxpayers every year.

(Reporting by Steve Gorman in Los Angeles; Editing by Michael Perry)