A bill to make it harder to buy handgun ammunition, including "cop-killer" bullets capable of piercing body armor, was endorsed today by local law enforcement.

Sen. Kevin de Leon, D-Los Angeles, said Senate Bill 124, which he introduced this week in the state Legislature, is designed to counteract a judge's decision Monday that struck down another pending state law that would have restricted sales of handgun ammunition.

Fresno County Superior Court Judge Jeffrey Hamilton blocked Assembly Bill 962, set to go into effect Feb. 1, which would have established new restrictions for purchasing certain types of ammo.

The law, which Hamilton declared "unconstitutionally vague," would have banned Internet sales of handgun ammo, requiring it be purchased in face- to-face transactions with identification and thumbprints.

In a news conference at the LAPD Administration Building, de Leon said he introduced SB 124 "to protect our law enforcement officers, who, every day must face danger while they protect the citizens of our state and our communities."

The bill, de Leon said, clarifies the definition of handgun ammunition in the Penal Code to make certain the state's ban on cop-killer bullets cannot be invalidated in the future.

Los Angeles Police Department Chief Charlie Beck urged the Legislature to pass the bill.

"It's a very simple ... but important law," Beck said. "By focusing on ammunition, we have an opportunity to reduce our death toll."

Police Protective League President Paul Weber said armor-piercing bullets were designed to penetrate protective vests like the one that saved Los Angeles Unified School District police officer Jeff Stenroos, who was shot in the chest last week while investigating a possible burglary in Woodland Hills.

If such bullets had been used by the gunman, who has not yet been identified, they "would have penetrated that vest and more than likely killed that officer," Weber said.

Beck said the Fresno judge's ruling jeopardizes California's efforts to track criminals who attempt to illegally acquire ammunition.

The bill amends the Penal Code to clarify the definition of "handgun ammunition" and cop-killer bullets. Specifically, de Leon's bill deletes the words "principally designed" and "primarily designed" from the Penal Code, which the California Rifle and Pistol Association Foundation successfully argued was too vague.