Threaded barrels are legal to own in Connecticut as a standalone part, but installing one on certain semi-automatic firearms can push the gun into “assault weapon” territory under Conn. Gen. Stat. § 53-202a. That classification matters: possessing an unregistered assault weapon is a Class D felony with a mandatory minimum of one year in prison.1Justia. Connecticut Code 53-202c – Possession of Assault Weapon Prohibited Whether your specific setup is legal depends on what kind of firearm the barrel is going on and what else is attached to it.
When a Threaded Barrel Becomes a Problem
Connecticut uses a feature test to decide when a semi-automatic firearm counts as an assault weapon. A threaded barrel is one of the listed features, but only on some types of firearms and only in combination with other conditions. The first question is always whether the firearm is semi-automatic. If it isn’t, threading is generally not an issue. If it is, the next question is what type of firearm you have, because the rules change from one category to the next.2Justia. Connecticut General Statutes 53-202a – Assault Weapons Definitions
Semi-Automatic Pistols
This is where a threaded barrel matters most. A semi-automatic pistol with a detachable magazine becomes an assault weapon if it also has any one of the following:
- A detachable magazine that attaches outside the pistol grip
- A threaded barrel capable of accepting a flash suppressor, forward pistol grip, or silencer
- A barrel shroud that lets the shooter fire without being burned (a standard slide doesn’t count)
- A second handgrip
Only one feature is required alongside the detachable magazine. A semi-automatic pistol with a detachable magazine and a threaded barrel is an assault weapon in Connecticut even if nothing is screwed onto the threads.2Justia. Connecticut General Statutes 53-202a – Assault Weapons Definitions
Semi-Automatic Centerfire Rifles
Rifles are treated differently, and this trips people up. A threaded barrel is not a listed feature for semi-automatic centerfire rifles. Under the current one-feature test, a semi-automatic centerfire rifle with a detachable magazine becomes an assault weapon if it has any one of these:
- A folding or telescoping stock
- A grip that lets any finger other than the trigger finger sit below the action, including pistol grips and thumbhole stocks
- A forward pistol grip
- A flash suppressor
- A grenade or flare launcher
A bare threaded barrel by itself does not put a centerfire rifle on that list. Screw a flash suppressor onto those threads, though, and the flash suppressor becomes the prohibited feature. A rifle can also qualify as an assault weapon if it has a fixed magazine holding more than ten rounds, or an overall length under thirty inches, regardless of threading.2Justia. Connecticut General Statutes 53-202a – Assault Weapons Definitions
Other Semi-Automatic Firearms
Connecticut’s 2023 assault weapon expansion, effective June 6, 2023, added a catch-all category for any semi-automatic firearm that isn’t classified as a pistol, revolver, rifle, or shotgun. This was aimed at platforms that blur the traditional categories, such as certain brace-equipped guns. For firearms in this category, a single feature makes the gun an assault weapon, and the list of features includes a threaded barrel capable of accepting a flash suppressor or silencer. There is no detachable-magazine prerequisite here. One feature is enough.3Connecticut General Assembly. Summary of PA 23-53 Addressing Gun Violence
Shotguns and Non-Semi-Autos
Threaded barrels are not listed as a prohibited feature for semi-automatic shotguns.2Justia. Connecticut General Statutes 53-202a – Assault Weapons Definitions The feature test also doesn’t reach bolt-action rifles, lever-action rifles, pump-action shotguns, or revolvers. You can thread the barrel on a bolt-action hunting rifle without any assault weapon concern.
Rimfire is a partial exception. The main rifle feature test in § 53-202a(1)(E)(i) applies to “semiautomatic, centerfire” rifles, so a semi-automatic rimfire rifle with a detachable magazine and a flash suppressor does not trigger that particular provision. Other parts of the assault weapon definition can still apply to certain rimfire firearms, so don’t assume rimfire alone puts you in the clear.2Justia. Connecticut General Statutes 53-202a – Assault Weapons Definitions
Keeping a Threaded Barrel Off the Gun
Storing the barrel separately doesn’t automatically protect you. Connecticut’s assault weapon definition includes “a part or combination of parts designed or intended to convert a firearm into an assault weapon” when those parts are under the same person’s control and could be rapidly assembled into a banned configuration. If you own a semi-automatic pistol with a detachable magazine and also keep a threaded barrel in your safe that fits that pistol, that provision can reach you. Licensed dealers and gunsmiths holding unassembled parts for servicing or repair are exempted.2Justia. Connecticut General Statutes 53-202a – Assault Weapons Definitions
What You Attach to the Threads
The muzzle device carries its own analysis.
Suppressors
Suppressors are legal for civilians in Connecticut who comply with the federal National Firearms Act process, which includes ATF Form 4, fingerprints, a photograph, and a background check. The federal NFA tax on suppressors dropped from $200 to $0 effective January 1, 2026, but registration, background checks, and wait times still apply.4Bureau of Alcohol, Tobacco, Firearms and Explosives. National Firearms Act Connecticut separately prohibits using a suppressor while hunting.5Justia. Connecticut Code 26-75 – Silencer on Firearms
Flash Suppressors
A flash suppressor is a prohibited feature under the feature test for semi-automatic centerfire rifles with detachable magazines, for semi-automatic pistols with detachable magazines (via the threaded barrel entry), and for the 2023 catch-all category. Screwing a flash hider onto the threads of a semi-automatic centerfire rifle with a detachable magazine turns the rifle into an assault weapon even though the bare threads would not.2Justia. Connecticut General Statutes 53-202a – Assault Weapons Definitions
Muzzle Brakes and Compensators
Muzzle brakes and compensators are generally permissible because they manage recoil and muzzle rise rather than flash. A device that functions as a flash suppressor can still trigger the classification regardless of what the manufacturer calls it, and hybrid devices advertised as both compensator and flash hider sit in a gray area. Read the manufacturer’s specifications carefully.
Pin and Weld
A common compliance path in feature-test states is permanently attaching a compliant muzzle device to the threaded barrel. Federal ATF guidance treats a muzzle device as permanently attached when it is welded, pinned with the pin head welded over, or attached with silver solder having a melting point of at least 1,100°F. Gunsmiths typically charge $25 to $150 for the work. Connecticut’s statutes don’t spell out whether a permanent attachment removes the “threaded barrel” characterization, so if you’re relying on this method, confirm the specific setup with a Connecticut firearms attorney before assembling the gun.
Penalties
Possessing an unregistered assault weapon is a Class D felony carrying a mandatory minimum of one year in prison that cannot be suspended or reduced, a maximum of five years, and a fine of up to $5,000.1Justia. Connecticut Code 53-202c – Possession of Assault Weapon Prohibited Distributing, importing, or selling an assault weapon is a Class C felony with a mandatory minimum of two years, a maximum of ten, and a fine of up to $10,000. Transferring one to a person under 18 adds a consecutive six-year mandatory minimum.6Connecticut General Assembly. Connecticut Code Chapter 943 – Offenses Against Public Peace and Safety
Judges have no discretion to go below those floors. A firearm that crosses into assault weapon status because of a threaded barrel on a semi-automatic pistol is treated the same as one banned by name. Registration deadlines for grandfathered assault weapons have all passed — the last one, for firearms lawfully owned on June 5, 2023, closed on May 1, 2024 — and there is no current mechanism to register retroactively.7Justia. Connecticut Code 53-202d – Certificate of Possession of Assault Weapon
Moving to Connecticut
New residents cannot register an incoming firearm that qualifies as an assault weapon under state law. Within 90 days of moving in, you must sell it to a licensed dealer (in-state or out-of-state), render it permanently inoperable, or relinquish it to a law enforcement agency. Keeping it past 90 days exposes you to a felony arrest.8State of Connecticut. Firearm Rules and Regulations If you’re relocating with firearms that have threaded barrels or other listed features, run each one through Connecticut’s feature test before the move, not after.