Los Angeles officials collected 950 guns during the city's weapon-purchase program on Saturday.
L.A. Mayor Eric Garcetti said that 13,000 firearms have been collected through the program since 2009, helping to decrease gun violence in the city.
"We'll never be able to say here's the causation," he said, "but you can be pretty darn sure -- collectively, these guns together -- one of them would've resulted in a tragedy."
The buyback was at four sites in Los Angeles on Saturday, one week after an Isla Vista man killed six people and wounded 13 near the campus of UC Santa Barbara.
L.A. officials collected 476 handguns, 273 rifles, 170 shotguns and 31 assault weapons on Saturday. Owners anonymously traded in their guns for Ralphs grocery gift cards of up to $200, depending on the type of weapon.
"Unwanted guns are guns that go unnoticed, and they fall in the wrong hands," said LAPD Chief Charlie Beck, "so they are the absolute best kind of weapons to get off the street."
"We make a concerted effort to keep guns out of the hands of gang members and the mentally ill, but unwanted guns are just as dangerous."
Most of the guns collected will be melted down and turned into rebar, Beck said.