To legally convert a pistol into a short-barreled rifle, you file ATF Form 1, wait for approval, engrave the receiver with your identifying information, and only then attach the stock. That is the entire lawful sequence for how to SBR a pistol, and reversing any step is a federal crime. The making tax dropped to $0 on January 1, 2026, so the paperwork no longer costs a $200 stamp, but the registration requirement itself is unchanged.1Office of the Law Revision Counsel. 26 USC 5821 – Making Tax Recent electronic Form 1 applications finalized in February 2026 averaged about 36 days to process.2ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives). Current Processing Times
What Counts as a Short-Barreled Rifle
Under the National Firearms Act, a short-barreled rifle is any rifle with a barrel under 16 inches, or any weapon made from a rifle with an overall length under 26 inches or a barrel under 16 inches.3Office of the Law Revision Counsel. 26 USC 5845 – Definitions A rifle is a weapon designed to be fired from the shoulder. A pistol is designed to be fired with one hand and has no stock.
Attach a shoulder stock to a pistol with a barrel under 16 inches, and you have built a weapon that fires from the shoulder with a short barrel. That is an SBR, and you are its maker. The NFA’s registration and (formerly tax) requirements apply before you can legally assemble it.4Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF). Application to Make and Register NFA Firearm
Check Your State’s Laws First
Federal approval does not override state law. Several states and the District of Columbia prohibit civilian ownership of short-barreled rifles entirely, and others impose additional restrictions or their own registration requirements. If your state bans SBRs, an approved Form 1 will not save you from a state possession charge. Confirm through your state legislature’s website or your local ATF field office before you spend any time on the federal paperwork.
Filing ATF Form 1
Form 1 (officially Form 5320.1) is the application to make and register an NFA firearm. Federal law requires you to file a written application, identify yourself and the firearm, pay any applicable tax, and receive ATF approval before making the firearm.5Office of the Law Revision Counsel. 26 USC 5822 – Making
The form asks for your full legal name, mailing address, and details about the firearm you plan to convert: manufacturer, model, serial number, and caliber. You also specify the barrel length and overall length the finished SBR will have. If the SBR will have a folding or collapsible stock, measure overall length with the stock extended.4Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF). Application to Make and Register NFA Firearm
Most applicants use the ATF eForms portal. Paper submissions by mail are also accepted but have historically taken longer to process.
Individual or Trust
You can file as an individual or through a legal entity such as an NFA gun trust or corporation. A trust lets multiple named people legally possess and use the SBR, which helps with shared use and estate planning. The trade-off is paperwork: every “responsible person” on the trust must submit fingerprints, a photograph, and a completed ATF Form 5320.23 (the Responsible Person Questionnaire).6Bureau of Alcohol, Tobacco, Firearms and Explosives. National Firearms Act (NFA) Responsible Person Questionnaire Responsible persons include trustees, grantors, officers, directors, and anyone else with authority over the trust or its firearms.
An individual filing is simpler, but you are the only person legally allowed to possess the SBR. If anyone else in your household could access it, a trust protects them from a federal possession charge.
Fingerprints, Photo, and Tax
Each applicant (or each responsible person on a trust) needs two completed FBI Form FD-258 fingerprint cards and a passport-style photograph. Local law enforcement offices and private fingerprinting services typically run about $30 to $85 per set. Electronic filers can upload a digital fingerprint file in .EFT format during submission, or mail paper FD-258 cards within 10 days of receiving a cover letter from the ATF.7Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Application To Make and Register NFA Firearm, ATF Form 5320.1 (Form 1)
The making tax for SBRs is $0 as of January 1, 2026. The statute now imposes the $200 tax only on machine guns and destructive devices; all other NFA firearms, including short-barreled rifles, carry a $0 making tax.1Office of the Law Revision Counsel. 26 USC 5821 – Making Tax The ATF still processes the application, runs the background check, and must approve it before you build anything.
Do Not Touch the Pistol While You Wait
This is where people get charged without realizing it. Federal courts recognize constructive possession: you can be charged with possessing an unregistered NFA firearm based on the parts you own, even if you never assembled them. A pistol, a short barrel, and a rifle stock sitting together in your home with no approved Form 1, and no other lawful use for the combination, can support a prosecution for possessing an unregistered SBR.
The practical rule while your Form 1 is pending: do not stage the stock alongside the pistol. If you already own a separate rifle that uses the same stock, the stock has a legitimate non-NFA purpose. If the only thing your on-hand parts could build is an unregistered SBR, that combination is the risk. Courts weigh proximity of parts, purchase timing, and whether any lawful configuration exists for the components on hand.
After Approval: Engrave, Then Assemble
When the ATF approves your Form 1, you get the approved application back. That document is your proof that the SBR is registered to you. One step comes before assembly: engraving.
What Has to Be Engraved
As the maker, you must mark the frame or receiver with your name (or the trust’s name) and the city and state where you made the SBR. If the firearm lacks a serial number, model designation, or caliber marking, you must add those as well. All markings must be engraved to a minimum depth of 0.003 inches, and the serial number must be printed no smaller than 1/16 inch.8Bureau of Alcohol, Tobacco, Firearms and Explosives. 27 CFR 479.102 – Identification of Firearms Most pistols already carry a serial number, model, and caliber from the factory, so in practice you usually only add your name (or trust name), city, and state.
Professional NFA engraving generally runs $40 to $100 depending on the shop and method, with laser typically slightly more than rotary. Engraving must be finished before you attach the stock.
Building the SBR
Once the receiver is engraved, you can physically attach the stock and complete the conversion. The build itself is often simple. On an AR-pattern pistol, for example, a buttstock swaps onto the buffer tube. The legal order is rigid: approved Form 1, then engraving, then assembly. Reversing any step is a federal violation.
Keep a copy of your approved Form 1 accessible whenever you transport or use the SBR. No federal statute requires you to carry it on your person, but having a paper or PDF copy available if law enforcement asks about registration saves significant trouble. A phone photo is a reasonable backup.
Traveling, Moving, and Selling
Taking your SBR across state lines requires advance ATF permission. Federal law prohibits an unlicensed person from transporting a short-barreled rifle in interstate commerce except as specifically authorized by the Attorney General.9Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts You submit ATF Form 5320.20 in duplicate to the NFA Division by mail, fax, or scanned email to NFAFax@atf.gov.10Bureau of Alcohol, Tobacco, Firearms and Explosives. Application to Transport Interstate or to Temporarily Export Certain National Firearms Act (NFA) Firearms The approved form specifies a time window; if you do not return the SBR home by that date, you need a new 5320.20. If you ship via commercial carrier, a copy of the approved form travels with the firearm. The destination state must also allow SBRs.
If you permanently move to a new state that allows SBRs, notify the ATF’s NFA Division in writing of your change of address.11U.S. Department of Justice, Bureau of Alcohol, Tobacco, Firearms, and Explosives. Application to Transfer and Register NFA Firearm (Tax-Paid) – ATF Form 5320.4
Selling or transferring the SBR to another private individual runs through ATF Form 4. The transferee submits fingerprints and a photograph, and the ATF must approve the transfer before the firearm changes hands.12ATF. NFA Handbook – Chapter 9 – Transfers of NFA Firearms The transfer tax for SBRs is also $0 as of 2026. The ATF will not approve a private transfer to an unlicensed individual in a different state; interstate private transfers must route through a licensed dealer.
Undoing the Conversion
To pull the firearm out of the NFA registry, convert it back to a configuration that no longer meets the SBR definition. For a pistol-origin SBR, that means removing the stock and returning it to pistol form. Then notify the ATF’s NFA Division in writing to remove the firearm from the registry. A firearm originally manufactured as a rifle cannot simply be shortened into a “pistol”; only firearms that started as pistols have this flexibility.
Penalties for Skipping the Process
Federal law lists several prohibited acts, including making an NFA firearm without approval and possessing a firearm not registered to you in the National Firearms Registration and Transfer Record.13Office of the Law Revision Counsel. 26 USC 5861 – Prohibited Acts A conviction carries up to 10 years in federal prison, a fine of up to $10,000, or both.14GovInfo. 26 USC 5871 – Penalties With the tax now at $0, the only cost of doing this the right way is time and a modest engraving bill. There is no reason left to skip the paperwork.