The U.S. Supreme Court has rejected a challenge by would-be gun dealers and a firearms organization to an Alameda County ordinance that bans new gun stores in unincorporated areas within 500 feet of a residential neighborhood, school or day care center.

The justices left intact a federal appeals court ruling that said the Second Amendment to the Constitution protects only the right to keep and bear arms, not the right to sell them. Lawyers for the county said similar buffer-zone ordinances are in effect in 17 other cities and counties in California, including San Francisco, Oakland and Contra Costa County.

The 1998 Alameda County ordinance was challenged by three businessmen who wanted to open a gun shop in an unincorporated area near San Leandro, 446 feet away from the nearest home on the other side of Interstate 880. Their suit, backed later in legal filings by the National Shooting Sports Federation, contended the county had effectively banned new gun stores in unincorporated areas and therefore violated the rights of prospective gun owners.

A three-judge panel of the Ninth U.S. Circuit Court of Appeals in San Francisco refused to dismiss the suit in 2016 and ruled 2-1 that the county, to justify the restriction, would have to prove it was essential to reducing gun crimes. But a majority of the full appeals court then granted the county’s request for a new hearing before a larger panel, which ruled 9-2 in October that the ordinance was constitutional.

There was no evidence that the local law “impedes any resident of Alameda County who wants to purchase a firearm from doing so,” Judge Marsha Berzon said for the court majority in October. She said the county has 10 gun stores, four of them in unincorporated areas and one of those within 600 feet of the proposed San Leandro location.

The Supreme Court denied review of that ruling on Monday.

The court’s “refusal to hear the case is disappointing but not surprising since they have ignored Second Amendment cases for nearly a decade,” said Craig Livingston, a lawyer for the National Shooting Sports Foundation. “The court missed an opportunity to weigh in on a clear split of authority between the majority of federal circuit courts of appeal and the Ninth Circuit, where the Second Amendment is plainly viewed as a second-class right.”

The high court has not taken up any substantial gun cases since rulings in 2008 and 2009 that found a constitutional right to possess handguns at home for self-defense.

Alan Gura, a lawyer for the businessmen who challenged the ordinance, declined to comment on the high court’s rejection.

Hannah Shearer, an attorney with the Giffords Law Center to Prevent Gun Violence, said the decision was “an important victory for local governments seeking to keep the sale and spread of guns away from kids and residential areas.”

The case is Texeira vs. Alameda County, 17-982.

Bob Egelko is a San Francisco Chronicle staff writer. Email: begelko@sfchronicle.com Twitter: @egelko