Senate Bill 503 establishes a Safe Firearm Disposal Incentive Grant Program, administered by the Department of Justice, to provide financial support to counties and law enforcement agencies that implement safe firearm disposal initiatives. The bill allocates $200,000 annually for these grants and creates a new position to oversee the program. Eligible applicants must propose a plan that includes advertising the program, utilizing law enforcement personnel, and ensuring proper handling and destruction of firearms. Additionally, the program must include safeguards against fraud and prevent the sale of firearms on-site.

The bill also outlines reporting requirements for grant recipients, including details on the firearms received and recommendations for program improvements. It ensures that grant funds do not replace existing funding for firearm disposal programs and provides immunity from prosecution for individuals submitting firearms under the program, with certain conditions. The Department of Justice is tasked with reporting to the legislature on the program's effectiveness and participation by July 1, 2028.