It occurred Feb 28th 1997. The AWB was already in effect. California AWB went into Effect Jan 1 2000. I say that because people keep saying 1994 the AWB wasn't a result of this well atleast not the fed one.
I believe it was a B&B gun shop which has since been run out of state.
http://www.cnn.com/US/9702/28/shootout.update/
Police borrow guns, ammo from a gun shop
Officers who initially responded to Friday's robbery, carrying standard-issue 9 millimeter Baretta handguns, were in trouble.
"Tactically, the first officers that arrived were at a severe disadvantage," weapons expert and former LAPD officer Dave Butler said. "Police carry 15 rounds. They would need to re-load."
Stunned officers were out-gunned to such a degree that at one point they burst into a gun store, and walked out with more powerful guns and ammunition.
Police "came in a panic because their weapons weren't good enough to fight these people," said the store's president, who would identify himself only as Bob.
"These people had body armor and they needed something that would break body armor," he said. "We supplied them with slugs that would at least break bones on someone wearing body armor."
Added the LAPD's McBride: "We have many suspects who have multiple guns, and they continue to out-gun us and fire at us at will."