Gun makers Smith & Wesson and Sturm, Ruger Co. said this week that a new California law requiring semiautomatic pistols to be equipped with technology called microstamping could result in fewer of their weapons available for sale in the state.

"Smith & Wesson does not and will not include microstamping in its firearms," the company said in a Thursday statement. Ultimately, California's mandate "will result in a diminishing number of Smith & Wesson semi-automatic pistols available for purchase by California residents."

Specifically, all M&P pistols other than the M&P Shield, will fall off California's roster of approved devices by August 2014 if the California law remains in place, Smith & Wesson said, "due to performance enhancements and other improvements we have made to those firearms." That includes the M&P9c (pictured).

California maintains a list of non-compliant handguns that can no longer be sold or manufactured in the state, which includes dozens of Smith & Wesson models.

Ruger, meanwhile, said it "will do all we can to fight this draconian law," and that "until microstamping is repealed, we expect that Ruger pistols – some of the safest available – will continue to be forced off the roster."

The microstamping law was actually approved in 2007 and signed into law by then-Governor Arnold Schwarzenegger. But it required certification by the California Department of Justice before it could go into effect, which didn't happen until last year. Now, it can move forward, much to the chagrin of gun makers.

Microstamping is "a microscopic array of characters that identify the make, model, and serial number of the pistol, etched or otherwise imprinted in two or more places on the interior surface or internal working parts of the pistol, and that are transferred by imprinting on each cartridge case when the firearm is fired," according to the state.

According to the Coalition to Stop Gun Violence, "microstamping technology utilizes lasers to make microscopic engravings on the breech face and firing pin of a gun. As the gun is fired, a code identifying the weapon's serial number is stamped onto the cartridge. This enables police to trace a gun without ever physically recovering it. A traced firearm is a valuable lead in a criminal investigation, because investigators can then connect that weapon to its first purchaser, who may become either a suspect or a source of information helpful to the investigation."

But James Debney, Smith & Wesson president and CEO, called microstamping an "unproven and unreliable concept."

Debney urged supporters to back a lawsuit filed by the National Shooting Sports Foundation (NSSF) and the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI), which seeks to invalidate the law.

"There is simply no existing microstamping technology that will reliably, consistently and legibly imprint the required identifying information by a semiautomatic handgun on the ammunition it fires," according to the groups.

The District of Columbia also has a microstamping law. Congress has addressed the issue, too, but nothing has been signed into law.