Twenty ATF agents working with Stockton Police and other local law enforcement agencies put 44 people behind bars during Operation Gideon.
At a news conference Tuesday, U.S. Attorney Ben Wagner announced that the effort has helped reduce violent crime in Stockton.
"Eighty-four firearms have been seized including 6 machine guns, 4 short barreled rifles and 2 silencers, approximately 36 pounds of methamphetamine, 21 pounds of marijuana, and significant amounts of heroin and crack cocaine were also recovered," said Wagner.
ATF Agent Joseph Riehl says all the people arrested face federal prosecution.
"[These include] people who conduct robberies and gang members who were responsible for numerous shootings," said Riehl. "Our concentrated efforts have been to ferret out the worst of the worst violent offenders."
Stockton Police Chief Eric Jones said Operation Gideon has already helped a city that reported a record 71 murders last year.
"We have seen reductions in our violence here in Stockton both with our homicides down about 50 percent and overall violence down about 15 percent," said Jones.
More arrests are expected soon.