“One bad apple spoils the whole bunch.”

The Brady Campaign to Prevent Gun Violence is using this famous proverb for an unprecedented campaign to stop irresponsible gun dealers from selling firearms to customers who pose a threat to public safety.

The “Bad Apple” national initiative seeks to hold dealers responsible for bypassing federal background checks laws, providing weapons to traffickers and permitting straw-man purchases that allow one person to buy a gun for another individual while lying about the true owner. The push includes concerted efforts to identify new lawsuits against irresponsible dealers, protests to place public pressure on vendors and demands for all suppliers to sign a code of conduct for lawful selling.

A “small and dangerous” group of firearms vendors are responsible for the toll of gun violence across the United States, said Dan Gross, president of the Brady Campaign. Just 1% of the dealers are accountable for providing 60% of the weapons used in crimes. Those business owners are the “bad apples,” he added.

Four local dealers supplied almost 20% of the guns recovered at crime scenes in Chicago between 2009 and 2013. The new initiative will kick off Saturday near the Windy City with a rally outside of Chuck’s Gun Shop & Pistol Range. The dealer consistently has been the worst offender for years, selling at least 1,516 guns that have led to violence, according to the Brady Campaign.

Also on Saturday, organizers will make public the locations of future protests and the specific code of conduct they are requesting each dealer to follow.

The Brady Campaign currently has eight lawsuits filed against separate gun dealers located in Alaska, Indiana, Kansas, Missouri, New York and Wisconsin. The activists on Monday are expected to charge a Pennsylvania supplier similarly with negligence.

During a media conference call on Friday, Gross acknowledged that the vast majority of dealers cooperate with public safety concerns — 80% of them report that not one gun used in a crime can be traced to their shelves.

The late James Brady, former President Ronald Reagan’s press secretary who died last month, became the namesake for the Brady Campaign in 2001. He was shot and seriously wounded two decades earlier during an assassination attempt on Reagan. Brady devoted his life to gun-control activism and pushed for legislation that would require a five-day waiting period and mandatory background checks for handgun purchases. Former President Bill Clinton signed the Brady Handgun Violence Prevention Act into law in 1993.

The Brady Campaign and other reformers continue to call on Congress to “finish the job” and resurface the gun-control debate.