Does Massachusetts Have an Assault Weapons Ban?

Massachusetts General Laws chapter 140, section 121 now defines an assault-style firearm through separate two-feature tests for semiautomatic rifles, pistols, and shotguns, an assault-style-firearm roster, named models, and a copy-or-duplicate test based on internal components or interchangeable receivers. For a semiautomatic centerfire rifle that accepts a detachable feeding device, the listed features are a folding or telescopic stock, a thumbhole stock or pistol grip, a forward or second handgrip, a threaded barrel designed to accommodate a flash suppressor or muzzle brake, and a barrel shroud.

Section 131M's retained-possession provision is tied to lawful Massachusetts possession on August 1, 2024 by a license holder and requires registration under section 121B and serialization under section 121C. The definition also excludes specified manual-action, permanently inoperable, antique, listed sporting, and limited shotgun categories.

The Legislature established the state assault weapons ban in 1998, and on July 20, 2016 the Attorney General issued an enforcement notice on what counts as a copy or duplicate of an enumerated weapon. Chapter 135 of the Acts of 2024 enacted the current definition and has been in effect since October 2, 2024 under an emergency preamble. Question 9 on the November 3, 2026 state election ballot is a referendum on Chapter 135: a yes vote keeps the law in place, and a no vote repeals it.

There has been no federal assault weapons ban since the 1994 ban expired in 2004; no feature restrictions apply federally to semi-automatic rifles or pistols. The 2023 ATF pistol-brace rule was vacated by the courts and is not enforced, but federal SBR classification for a brace-equipped firearm still turns on whether the specific weapon is designed and intended to be fired from the shoulder. Garland v. Cargill (2024) held that a bump stock is not a machine gun under federal law. Feature bans are entirely a matter of state law.

Federal baseline verified 2026-10-20. Scope: State laws restricting semi-automatic rifles, pistols, and shotguns by configuration features: threaded barrels, pistol grips, folding or telescoping stocks, flash suppressors, forward grips, and similar. Magazine capacity limits are tracked as a separate class.