State Legality MatrixBinary TriggersMassachusetts
Statute-cited, not legal advice, last verified 2026-10-20
Banned
No. Prohibited as a trigger modifier; 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
Chapter 135 of the Acts of 2024 (approved July 25, 2024; in effect October 2, 2024 under an emergency preamble) defines a trigger modifier as any modification that repeatedly activates the trigger, including trigger cranks, binary triggers, and hellfire triggers. Chapter 269, § 10(c) punishes possession of a trigger modifier, bump stock, rapid-fire trigger activator, or automatic part by state-prison imprisonment for life or any term of years. Question 9 on the November 3, 2026 state ballot is a referendum on Chapter 135: a yes vote keeps the law and a no vote repeals it.
The statute in practice
General Laws chapter 140, section 121 defines a trigger modifier as any modification that repeatedly activates the trigger of a firearm, including trigger cranks, binary triggers, and hellfire triggers. Chapter 269, section 10(c) punishes owning or possessing a trigger modifier, bump stock, rapid-fire trigger activator, or automatic part by imprisonment in the state prison for life or for any term of years.
Timeline
In the legislature
Asks voters whether to approve Chapter 135 of the Acts of 2024. A yes vote keeps the law in place; a no vote repeals it.
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.
Federal baseline verified 2026-10-20. 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 trigger modifier; 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 trigger modifier; the 2024 firearms law names binary triggers.
Massachusetts's rule took effect 2024-10-02. Chapter 135 of the Acts of 2024 (approved July 25, 2024; in effect October 2, 2024 under an emergency preamble) defines a trigger modifier as any modification that repeatedly activates the trigger, including trigger cranks, binary triggers, and hellfire triggers. Chapter 269, § 10(c) punishes possession of a trigger modifier, bump stock, rapid-fire trigger activator, or automatic part by state-prison imprisonment for life or any term of years. Question 9 on the November 3, 2026 state ballot is a referendum on Chapter 135: a yes vote keeps the law and a no vote repeals it.
Chapter 140, section 121 supplies the trigger-modifier definition that names binary triggers, and chapter 269, section 10(c) supplies the possession offense.