Long gun sales in California declined 54 percent last month, one year after the bullet button ban sparked a six-month selling frenzy.

California dealers submitted 21,721 applications for long guns through the FBI’s National Instant Criminal Background Check System in July, less than half of nearly 48,000 processed in 2016. The surge came in the weeks and months after Gov. Jerry Brown signed a package of gun control bills.

Dealers reported the bullet button ban, in particular, kick-started a boon that led to record-breaking background checks — and by proxy, sales — through the end of the year.

Brown signed a bill July 1 outlawing guns outfitted with bullet buttons as part of a package of legislation drafted in response to the Dec. 2, 2015 San Bernardino mass shooting.

The ban bill also stipulated gun owners already in possession of the outlawed weapons would be required to register the firearms with the state.

Christopher Lapinski, operations manager at Last Stand Readiness & Tactical in Sacramento, told local news outlets last year he’d noticed more customers looking for weapons with the bullet buttons — a magazine quick-release mechanism operated with a small tool — before the expanded laws took effect in January.

“They call it a bullet button because you would use a bullet to eject this magazine from the magazine well here,” Lapinski said during an interview with Fox 40. “The whole anti-gun movement, taking guns from citizens, literally has everyone and their grandmother buying firearms before they can’t get them anymore because they want to be able to be protected.”

Federal data shows California long gun checks surged to number one nationwide in July 2016, outpacing Texas — the second busiest state that year — by nearly 40 percent.

This year, California’s long gun checks slipped to number two, trailing Texas by 20 percent and less than 3,000 checks ahead of the third busiest state, Florida.

In June, state regulators rejected the California Department of Justice’s proposed new rules on which weapons would qualify under the state’s ban and how the registration process should work. That same month, Brown extended the registration deadline by six months to July 1, 2018.

This is the second time justice officials hit a snag drafting these rules — the department withdrew a previous draft in February without explanation.