State Legality MatrixBinary TriggersMaryland
Statute-cited, not legal advice, last verified 2026-10-20
Banned
No. Expressly prohibited: the rapid fire activator definition names binary trigger systems. Effective 2018-10-01.
Controlling law: Md. Code, Crim. Law § 4-301 (definitions) & § 4-305.1
Contested entry
Chapter 252 of 2018 (effective October 1, 2018) created the ban with binary trigger systems named; § 4-301 defines a binary trigger system as a device that fires both when the trigger is pulled and on release. Chapter 713 of 2024 (effective October 1, 2024) renamed the term rapid fire activator and added switches and auto sears, and Chapter 771 of 2026 (effective October 1, 2026) added pistol converters. Section 4-305.1 bars transporting one into the state and manufacturing, possessing, selling, transferring, purchasing, or receiving one, with a narrow exception for devices held before October 1, 2018 under specified ATF authorization conditions. The Fourth Circuit affirmed dismissal of takings and vagueness challenges to the 2018 law in Maryland Shall Issue v. Hogan (No. 18-2474, June 29, 2020).
The statute in practice
Maryland Criminal Law section 4-301 defines a binary trigger system as a device that fires both when the trigger is pulled and on release of the trigger, and lists it within the rapid fire activator definition alongside bump stocks, trigger cranks, hellfire triggers, and burst systems. Section 4-305.1 bars transporting a rapid fire activator into the state and manufacturing, possessing, selling, offering to sell, transferring, purchasing, or receiving one.
Timeline
What it means for you
Section 4-305.1(b) exempts possession only by a person who possessed the device before October 1, 2018, applied to ATF for authorization before that date, received ATF authorization before October 1, 2019, and complies with all federal requirements.
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. Expressly prohibited: the rapid fire activator definition names binary trigger systems. Effective 2018-10-01. Controlling law: Md. Code, Crim. Law § 4-301 (definitions) & § 4-305.1.
The controlling law is Md. Code, Crim. Law § 4-301 (definitions) & § 4-305.1. Expressly prohibited: the rapid fire activator definition names binary trigger systems.
Maryland's rule took effect 2018-10-01. Chapter 252 of 2018 (effective October 1, 2018) created the ban with binary trigger systems named; § 4-301 defines a binary trigger system as a device that fires both when the trigger is pulled and on release. Chapter 713 of 2024 (effective October 1, 2024) renamed the term rapid fire activator and added switches and auto sears, and Chapter 771 of 2026 (effective October 1, 2026) added pistol converters. Section 4-305.1 bars transporting one into the state and manufacturing, possessing, selling, transferring, purchasing, or receiving one, with a narrow exception for devices held before October 1, 2018 under specified ATF authorization conditions. The Fourth Circuit affirmed dismissal of takings and vagueness challenges to the 2018 law in Maryland Shall Issue v. Hogan (No. 18-2474, June 29, 2020).