Yes, you can buy a lower receiver, but the process is the same one you’d follow to buy a complete rifle: you must be at least 21, a legal resident of the state where the sale happens, not fall into any federally prohibited category, and complete the transfer through a licensed dealer after passing a background check. Federal law treats the receiver itself as the firearm, so a bare stripped lower on a shelf carries the same rules as a finished gun.1Office of the Law Revision Counsel. 18 USC 921 – Definitions
Why the Receiver Is Regulated Like a Whole Gun
Barrels, stocks, handguards, bolt carrier groups, and triggers can all be shipped straight to your door with no paperwork. The receiver is the one part that carries a serial number and requires a legal transfer through a licensed dealer, because federal law defines the frame or receiver as the “firearm.”2Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Summary of Final Rule 2021R-05F – Definition of Frame or Receiver That’s the reason everything below applies to what looks, to a beginner, like just a metal shell.
Age, Residency, and Who Is Prohibited
You must be 21 to buy a stripped lower from a dealer. That surprises some buyers, since a complete rifle or shotgun can be purchased at 18. A stripped receiver isn’t yet a rifle or shotgun, so it falls under the ATF’s “other firearm” category, which carries the higher age floor.3Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Firearms Questions and Answers The 21 rule applies even if you plan to build a long gun from it.4Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts
You also need to be a legal resident of the state where the sale happens. A licensed dealer can’t sell a firearm classified as “other” to someone who lives out of state. If you find a receiver at a shop while traveling, the dealer has to ship it to an FFL back in your home state.
Federal law bars several categories of people from possessing any firearm or ammunition, including a lower receiver:4Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts
- Anyone convicted of a crime punishable by more than one year in prison
- Fugitives from justice
- Current unlawful users of controlled substances as defined under federal law
- Anyone found mentally defective by a court or committed to a mental institution
- Anyone illegally in the United States, or admitted under a nonimmigrant visa with limited exceptions
- Anyone dishonorably discharged from the military
- Anyone who has renounced U.S. citizenship
- People subject to a qualifying protective order restraining them from harassing, stalking, or threatening an intimate partner or their child, issued after a hearing with specific judicial findings
- People convicted of a misdemeanor crime of domestic violence
Possessing a firearm while falling into any of these categories is a federal felony punishable by up to 10 years in prison.5Department of Justice. Quick Reference to Federal Firearms Laws Some of these, like the drug use provision, don’t require a conviction; they apply based on current status.
How the Purchase Works
Every dealer sale starts with ATF Form 4473, the Firearms Transaction Record. You fill it out at the dealer’s premises. It asks for your full legal name, residential address, date and place of birth, and a series of yes-or-no questions about your eligibility.6Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Firearms Transaction Record – ATF Form 4473 Providing a Social Security number is optional, but the FBI recommends it because common names frequently cause delays or mismatched records during the background check.
Bring a valid government-issued photo ID showing your current address. If your driver’s license still lists an old address, most dealers will accept a second government document confirming your current residence, like a vehicle registration or a recent tax notice. Every answer on the 4473 is given under penalty of perjury, and false statements are a separate federal crime.
Once the form is complete, the dealer contacts the National Instant Criminal Background Check System, run by the FBI. The system searches criminal history records, mental health adjudications, and other disqualifying databases.7Federal Bureau of Investigation. Firearms Checks (NICS) In most cases the response comes back within minutes as “proceed,” “delayed,” or “denied.” A “proceed” means you can walk out with the receiver.
Ordering Online
You can order a lower receiver from an online retailer, but it can’t ship to your home. The seller sends it to a Federal Firearms Licensee (FFL) near you. When it arrives, you go in, fill out the Form 4473, and complete the background check exactly as you would for any in-store purchase. The local dealer charges a transfer fee, which varies widely: under $25 at high-volume shops, over $75 at smaller ones. Calling a few local FFLs before you order is the easiest way to avoid overpaying.
A completed NICS check is valid for 30 calendar days from when it was initiated. If you don’t pick up the receiver within that window, the dealer has to run a new check.8Federal Bureau of Investigation. NICS Federal Firearms Licensee Manual If you decide to add another firearm to the transaction after signing your 4473, that also triggers a new form and a new NICS check.
If the Background Check Is Delayed or Denied
A “delayed” result means the FBI needs more time to research a potential match. This is common for people with common names, prior arrests that were dismissed, or records from states with incomplete data reporting. The law gives the FBI three business days to resolve it. If no final “denied” response comes within that window, the dealer is legally permitted to complete the transfer.4Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts The dealer isn’t required to, and many choose to wait for a definitive answer.
A “denied” result means the system found a disqualifying record. If you believe the denial was an error, you can appeal through the FBI’s NICS Section. People who see repeated delays or erroneous denials can apply for a Unique Personal Identification Number through the FBI’s Voluntary Appeal File. A UPIN links your identity to verified records so the system can distinguish you from anyone with a similar name. Applications require a completed form and fingerprint card and can be submitted electronically or by mail. There’s no fee.9Federal Bureau of Investigation. Voluntary Appeal File
Private Sales and Straw Purchases
Federal law only requires a background check when a licensed dealer is involved. If two private individuals in the same state agree to a sale, federal law doesn’t mandate it go through an FFL. But a growing number of states have closed that gap by requiring all firearm transfers, including private sales of lower receivers, to run through a licensed dealer with a background check. And selling to someone you know or have reason to believe is a prohibited person is a federal crime regardless of whether a dealer is involved.
There’s also a line between occasionally selling a firearm you own and “engaging in the business” of dealing. You don’t need a license to sell a receiver from your personal collection once in a while. Buy and resell receivers with any regularity for profit, though, and the ATF may treat it as unlicensed dealing.10Office of the Law Revision Counsel. 18 USC 923 – Licensing
The biggest legal hazard in this area is the straw purchase. That’s when you buy a receiver on behalf of someone else, either because they’re prohibited or because they want to skip the background check. The Bipartisan Safer Communities Act of 2022 created a standalone federal crime for it, with a maximum penalty of 25 years in prison.11Office of the Law Revision Counsel. 18 USC 932 – Straw Purchasing of Firearms Fines can reach twice the gross proceeds of the offense, and a conviction triggers forfeiture of any property derived from or used to facilitate the crime.12Federal Register. Bipartisan Safer Communities Act Conforming Regulations
The 4473 question that catches straw buyers asks whether you are the “actual transferee/buyer.” Buying a receiver as a gift is legal, and you’d answer yes. But if someone hands you money and asks you to go buy one for them, you are not the actual buyer, and answering yes is a federal crime. Dealers are trained to watch for red flags, like someone else picking out the item while the “buyer” just handles the paperwork.
What You Plan to Build Matters
Federal law lets you manufacture a firearm for personal use without a license, as long as you could otherwise legally possess it and don’t intend to sell it.13Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Chapter 7 – Manufacturing NFA Firearms What you build changes the legal picture.
The critical threshold is barrel length. Attach a rifled barrel shorter than 16 inches and a stock, and you’ve created a short-barreled rifle, which is regulated under the National Firearms Act. Making one without first obtaining ATF approval on a Form 1 and paying the $200 tax is a federal felony. The same applies to any configuration with an overall length under 26 inches. You can legally build a pistol-configuration firearm with a short barrel and no stock, since that doesn’t meet the definition of a rifle. But once a lower receiver has been assembled as a rifle, converting it back to a pistol configuration creates legal complications. The order of assembly matters more than most people realize.
Build a standard rifle with a 16-inch or longer barrel and at least 26 inches of overall length, and no NFA paperwork is needed. That’s an ordinary Title I firearm, legally no different from a factory rifle you’d buy off the shelf.
80% Receivers After the 2022 Rule
Partially machined “80% receivers” used to sit outside federal firearm rules, and buyers could order them without a background check and finish the machining at home. The ATF’s 2022 final rule changed that. Under the updated definition, a partially complete frame or receiver that can “readily be completed, assembled, restored, or otherwise converted to function” now counts as a regulated firearm.14Federal Register. Definition of Frame or Receiver and Identification of Firearms A parts kit sold with a jig, template, or drill-indexed blank falls squarely within the new definition. Raw materials like unformed blocks of metal or liquid polymer are still excluded, but anything that looks recognizably like a receiver and can be finished with common tools and online instructions is now treated as one.2Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Summary of Final Rule 2021R-05F – Definition of Frame or Receiver
The rule also created requirements for what the ATF calls “privately made firearms.” If you already finished an 80% receiver at home, you aren’t required to serialize it yourself for personal use. But the moment that receiver enters the commercial stream, the rules change. Any licensed dealer who takes in a privately made firearm must engrave a serial number on it within seven days of receiving it, or before reselling it, whichever comes first.15ATF eRegulations. 27 CFR 478.92 – Identification of Firearms and Armor Piercing Ammunition by Licensed Manufacturers and Licensed Importers The serial number must start with the dealer’s abbreviated FFL number as a prefix. The rule has faced legal challenges, but as of early 2026 the ATF continues to treat it as in effect.
State Rules Can Go Further
State laws can add layers of regulation that go well beyond the federal baseline. Some jurisdictions ban specific receiver types used to build firearms they classify as assault weapons. Others impose waiting periods between purchase and delivery that apply to all firearms, including receivers classified as “other.” A handful of states require every firearm transfer, including private sales, to run through a licensed dealer with a background check.
Some states also have their own serialization mandates for privately made firearms, requiring registration with a state agency regardless of federal law. Violating a state-level restriction can bring felony charges and a permanent loss of firearm rights, even if the receiver is perfectly legal under federal law. Because these rules vary widely and change often, checking your state’s current statutes before you buy is the single most useful step you can take to avoid an unintentional violation.