An upcoming ruling in a California federal appeals court could have a big impact on the firearms industry and the future of so-called “smart gun” technology, according to this story from the Wall Street Journal.

The Ninth U.S. Circuit Court of Appeals in San Francisco, which covers a wide swath of the West, will rule soon on a challenge to a California law requiring gun manufacturers to make handguns that won’t fire a bullet left in the chamber if their magazines are detached, and that will indicate when a bullet is in the chamber.

Firearms with a magazine disconnect feature will not fire a round in the chamber when the mag is removed, but most modern handguns don’t have this feature. This is to allow the user to fire at least one round if the magazine release should be hit accidentally, rendering the gun unloaded or causing it not to feed.

Many handguns on the market do feature a loaded-chamber indicator of some kind. Both measures have been around for more than a century in the firearms industry, but the ruling is likely to inform any efforts by states to mandate newer technologies like “smart gun” tech, recently promoted by the Obama administration, which would prevent the gun from firing in the hands of an unauthorized user.

“How the Ninth Circuit rules here will have a huge impact on the ability of any state to require any kind of smart gun technology,” said Adam Skaggs, senior counsel for the Michael Bloomberg-funded Everytown For Gun Safety anti-gun group, in the story.

Last month, Obama laid out a framework for federal law enforcement agencies to begin purchasing and using smart guns, as soon as a reliable one is invented, and pledged grant money to state and local governments to buy their own. The idea, the administration says, is not to force the tech on any one, but to spur its development.

Law enforcement personnel have spoken out since in objection to being Guinea pigs for a technology that, if it fails, could mean the difference between life and death.

But gun rights groups say they fear that the adoption of smart-gun tech by some will lead states to require it for all.

“Somebody comes out with a smart gun and then a state mandates that it’s the only type of gun you can own. That’s what our concern is,” said Alan Gottlieb, founder of the Second Amendment Foundation, in the WSJ story.

There is precedent for this, as New Jersey passed a law in 2002 saying that once the technology is available on the market, that is the only type of handgun that may be sold in the state.

In 2014 a german company made a handgun designed only to work when paired with an accompanying wristwatch, a product that almost put the NJ law into effect.

Ultimately, it was deemed that the product didn’t line up with the definition of a smart gun in the NJ legislation, as the gun could be fired by anyone wearing the wristwatch, not just the “registered” user.

Since 1997, the Justice Department wasted nearly $13 million in federal grants to promote smart-gun tech, but so far, a commercially viable firearm is still waiting to be made.

The NRA has repeatedly made it clear that it doesn’t oppose smart-gun technology, but only the mandating of the technology.

California already has a lot of rules regarding handguns. The law requiring the magazine-disconnect and loaded chamber indicator features was passed in 2003. In 2007, another provision of the state’s Unsafe Handgun Act requires firearms sold in the state to be capable of imprinting ammo casings with a tiny script that ballistic experts can trace back to the gun, a process called microstamping, the story says.

In 2009 the SAF and another gun rights group, the Calguns Foundation, sued the state, saying the provisions violate the Second Amendment because they bar the purchase of many types of handguns that are in common use.

According to the story, magazine-disconnect mechanisms and loaded-chamber indicators are available on 11 to 14 percent of semi-auto handguns, but those numebrs are from a 1999 survey from Johns Hopkins, the story says.

So far, no firearms manufacturer has submitted any handguns featuring microstamping technology for listing on California’s allowable guns.

“Scores of common, popular firearms are being banned not because they malfunction, but because the legislature dislikes the mann in which Second Amendment arms work,” said Alan Gura, an attorney representing the gun rights groups.