Massachusetts Question 9 is a referendum on the state’s 2024 “Act Modernizing Firearm Laws.” The law expanded rules involving firearm registration and serialization, privately made and untraceable firearms, assault-style firearms, licensing and safety training, and related enforcement provisions. State officials also described the law as strengthening the red-flag framework and addressing ghost guns and 3-D-printed guns. Because the referendum can reverse a large package rather than one isolated provision, voters face the broader question of whether the law’s safety gains justify its cumulative burdens on lawful gun owners. Serialization and background rules can help investigations, but a large firearms bill can also impose requirements on people who have committed no crime. The useful choice is not “guns versus safety,” but which provisions produce enough safety value to justify their burden.