Yes, you can buy AR parts in Illinois, but the Protect Illinois Communities Act (PICA) has taken a long list of the most common components off retail shelves since January 10, 2023. Accessories like optics, lights, and slings are unrestricted. Function-defining parts — pistol grips, threaded barrels, flash suppressors, telescoping stocks, buffer tubes, and standard-capacity magazines — are not, and lower receivers still move through a federally licensed dealer with a FOID card in hand.
Parts You Cannot Buy
PICA regulates two things at the parts level: components that turn a firearm into a banned assault weapon, and a separate category the statute calls “assault weapon attachments.” The Illinois State Police publishes an illustrative list, and the list is not exhaustive.1Illinois State Police. Protect Illinois Communities Act, Regulation on Assault Weapons Anything meeting the statutory definition can qualify even if it is not named.
The attachments ISP has identified as regulated include:
- Folding, telescoping, thumbhole, or detachable stocks, or any stock that reduces overall dimensions or improves concealability
- Pistol grips, thumbhole stocks, or any protruding grip the non-trigger hand can hold
- Flash suppressors
- Threaded barrels and barrel shrouds that let you hold the firearm without being burned
- Buffer tubes, arm braces, or similar parts that protrude behind the pistol grip and permit shoulder firing
- Grenade launchers
Magazines get their own restriction. PICA bans magazines, belt-fed devices, drums, and similar feeding devices holding more than 10 rounds for long guns or more than 15 rounds for handguns, and it covers any combination of parts that could be assembled into one.1Illinois State Police. Protect Illinois Communities Act, Regulation on Assault Weapons The 30-round magazine that ships standard with most AR builds is out.
Lower receivers sit at the center of this. Federal law and Illinois law both treat the lower as the firearm itself, and under the ATF’s frame-and-receiver rule effective August 2022 the AR-15/M-16 lower stays the serialized component.2Federal Register. Definition of Frame or Receiver and Identification of Firearms ISP has confirmed that receivers designed or intended to convert a firearm into an assault weapon are regulated under PICA. A stripped lower that can be assembled into a prohibited configuration falls inside the statute.
Parts You Can Still Buy
ISP draws the line at components integral to a firearm’s basic function and at items not specifically designed for a firearm at all. The state police have expressly identified these as outside the attachment definition:
- Scopes and scope mounts
- Red dot sights, holographic sights, and their mounts
- Laser sighting devices
- Flashlights and other lighting devices
- Slings and sling mounts
Cleaning kits, tools, and general maintenance accessories are also unaffected.1Illinois State Police. Protect Illinois Communities Act, Regulation on Assault Weapons Magazines at or below 10 rounds for a rifle remain legal to purchase.
Upper receivers are a gray area. A bare upper without a barrel or other prohibited features is not itself on the restricted list. Add a threaded muzzle, flash suppressor, or barrel shroud and the assembly becomes something the statute reaches. If you are building an upper, every feature has to be examined on its own.
The .22 Rimfire Carve-Out
PICA exempts tubular magazines designed to accept and operate only with .22 caliber rimfire ammunition from both the fixed-magazine definition and the capacity ban.3Illinois General Assembly. Illinois Code 720 ILCS 5/24-1.9 – Manufacture, Possession, Delivery, Sale, and Purchase of Assault Weapons A lever-action .22 with a tube magazine over 10 rounds is fine on that basis. The exemption is narrow. It applies to the magazine type, not to any firearm as a whole, and PICA’s by-name ban list includes specific .22 LR AR-style rifles such as the Armalite M15 22LR Carbine. A rifle banned by name stays banned regardless of caliber.
Before You Buy Anything: FOID and FFL
A valid Firearm Owner’s Identification card issued by the Illinois State Police is required before any firearm or ammunition purchase in Illinois.4Illinois.gov. Apply for a Firearm Owners Identification Card That includes a stripped lower and a box of .22 rounds alike.
Because the lower is legally a firearm, buying one runs through a Federal Firearms Licensee: NICS background check, ATF Form 4473, the full transfer.5Bureau of Alcohol, Tobacco, Firearms and Explosives. Federal Firearms Licensee Quick Reference and Best Practices Guide An online purchase ships to your FFL, not your door. Illinois adds a 72-hour waiting period on all firearm deliveries, measured from the time buyer and seller reach an agreement to purchase.6Illinois Firearm Dealer Portal. Frequently Asked Questions Expect a transfer fee from the FFL, commonly $25 to $50 on top of the price of the part.
Parts that are not firearms — optics, unrestricted handguards, slings, cleaning gear — can generally ship directly to your address with no FFL involvement.
If You Already Own a Grandfathered AR
If you legally owned an assault weapon, attachment, or high-capacity magazine before January 10, 2023, PICA lets you keep it, but only with an electronic endorsement affidavit filed through the ISP’s FOID portal. The original deadline for existing residents was January 1, 2024.7Cornell Law School. Illinois Admin Code Title 20, 1230.15 – FOID Card and Assault Weapon Electronic Endorsement Affidavit Requirement ISP has said the portal stays open indefinitely, and no separate fine attaches to a late filing, but a local prosecutor could deem a late submission invalid, and possessing regulated items without a valid endorsement violates both the FOID Act and the Criminal Code.1Illinois State Police. Protect Illinois Communities Act, Regulation on Assault Weapons
Buying Parts to Repair a Registered Rifle
Even with a valid endorsement, you cannot walk into a store and buy a replacement attachment for your grandfathered rifle. PICA permits repairs, with a split based on the part. Small internal parts that are not themselves regulated attachments — a trigger spring, a gas ring — you can source and install yourself. A regulated attachment, such as a telescoping stock or buffer tube, has to be ordered and installed by an FFL or gunsmith, and the repair cannot include additional attachments beyond what makes the firearm functional again.1Illinois State Police. Protect Illinois Communities Act, Regulation on Assault Weapons A shop cannot use a repair as a pretext to add features. You also need a valid endorsement on file to legally transport the rifle to the gunsmith.
Penalties for Getting It Wrong
Possessing an assault weapon or prohibited attachment without proper registration is a Class A misdemeanor on a first offense, with fines up to $2,500. A second or later possession charge is a Class 2 felony with fines up to $25,000, carrying a potential prison sentence of three to seven years. Manufacturing, selling, or delivering assault weapons or attachments is a Class 3 felony, also with fines up to $25,000.
The gap between “I thought it was legal” and a felony charge is a component that fits the attachment definition. If a part’s status is unclear, confirming with an FFL before purchase costs nothing compared to what a wrong guess costs after.
The Law Is Being Challenged, But It Is in Effect
PICA is the subject of active federal litigation. In Harrel v. Raoul, plaintiffs challenged the statute under the Second Amendment. The U.S. Supreme Court denied certiorari in July 2024, and the case continued in the Seventh Circuit Court of Appeals, which heard oral arguments in September 2025. A Seventh Circuit ruling could narrow or strike PICA’s restrictions. Until then every provision above is in force, and every part purchase in Illinois is governed by the statute as written.