State Legality MatrixBinary TriggersMassachusetts
Statute-cited, last verified 2026-07-31
Banned
No. Prohibited as a rapid-fire trigger activator; the 2024 firearms law names binary triggers. Effective 2024-10-02.
Controlling law: Mass. Gen. Laws ch. 140, § 121 (definitions); ch. 269, § 10(c); St. 2024, c. 135
Contested entry
Massachusetts banned bump stocks and trigger cranks in 2018; Chapter 135 of the Acts of 2024 added rapid-fire trigger activator coverage that expressly includes binary triggers and hellfire triggers, effective October 2, 2024 under the emergency preamble. No licensing exception permits possession.
The statute in practice
General Laws chapter 140, section 121 defines 'trigger modifier' to include a binary trigger and places trigger modifiers within the broader rapid-fire-trigger-activator framework. The possession offense appears in chapter 269, section 10(c); section 131M is the assault-style-firearm and large-capacity feeding-device provision, not the operative binary-trigger subsection.
Timeline
What it means for you
For a current Massachusetts analysis, read the definitions in chapter 140, section 121 together with the conduct and penalty language in chapter 269, section 10(c). A license category does not replace that device-specific inquiry.
Federal law
Binary triggers are legal under federal law and are not machine guns under 26 U.S.C. § 5845(b); ATF treats the trigger pull and the trigger release as two separate functions of the trigger, so one round is fired per function. Cargill v. Garland (2024) concerned bump stocks, not binary triggers, and does not change this.
Scope: Binary triggers (Franklin Armory BFSIII and similar): fire one round on trigger pull and one on release. Forced reset triggers are a separate class.
Common questions
No. Prohibited as a rapid-fire trigger activator; the 2024 firearms law names binary triggers. Effective 2024-10-02. Controlling law: Mass. Gen. Laws ch. 140, § 121 (definitions); ch. 269, § 10(c); St. 2024, c. 135.
The controlling law is Mass. Gen. Laws ch. 140, § 121 (definitions); ch. 269, § 10(c); St. 2024, c. 135. Prohibited as a rapid-fire trigger activator; the 2024 firearms law names binary triggers.
Massachusetts's rule took effect 2024-10-02. Massachusetts banned bump stocks and trigger cranks in 2018; Chapter 135 of the Acts of 2024 added rapid-fire trigger activator coverage that expressly includes binary triggers and hellfire triggers, effective October 2, 2024 under the emergency preamble. No licensing exception permits possession.
Binary triggers are legal under federal law and are not machine guns under 26 U.S.C. § 5845(b); ATF treats the trigger pull and the trigger release as two separate functions of the trigger, so one round is fired per function. Cargill v. Garland (2024) concerned bump stocks, not binary triggers, and does not change this.
Chapter 140, section 121 supplies the definitions; chapter 269, section 10(c) supplies the possession offense. Chapter 140, section 131M governs a different set of assault-style-firearm and feeding-device conduct.