Destructive devices under the NFA are a separate class of regulated firearm covering three things: any weapon with a bore larger than one-half inch, any explosive or chemical munition such as a grenade, bomb, mine, rocket, or poison gas device, and any collection of parts that could be readily assembled into either. Legal ownership is possible for most private citizens, but it requires ATF registration on the National Firearms Act registry, a $200 federal tax on every transfer or manufacture, fingerprints, photographs, a background check, and compliance with state law. The $200 tax on destructive devices did not go away in the 2026 NFA tax changes.
What Qualifies as a Destructive Device
The statutory definition sits at 26 U.S.C. § 5845(f) and has three branches.1Office of the Law Revision Counsel. 26 USC 5845 – Definitions
Large-Bore Weapons Over Half an Inch
Any weapon that expels a projectile through a barrel with an interior diameter greater than one-half inch is a destructive device. The language reaches “any type of weapon by whatever name known,” so anti-tank rifles, 20mm autocannons, and similar hardware all fall inside. The cutoff sits just above the .50 BMG cartridge, which measures .510 inches in most rifles chambered for it. Anything built around a larger cartridge triggers registration unless a specific exclusion applies.
The statute also catches weapons that “may be readily converted” to fire through an oversized bore. A finished, functional gun is not required. If the piece can be made operational without significant machining, ATF treats it as a destructive device.
Explosive, Incendiary, and Chemical Munitions
The second branch covers ordnance regardless of size:
- Bombs and mines designed to detonate by impact, timer, or remote trigger
- Grenades, hand-thrown or launcher-fired, with no minimum explosive weight
- Rockets containing more than four ounces of propellant
- Missiles carrying more than one-quarter ounce of explosive or incendiary material
- Incendiary devices built to ignite fires or destroy through heat
- Poison gas delivery systems
Each individual munition is its own registered item. Five grenades means five registrations and five $200 tax payments.2Office of the Law Revision Counsel. 26 USC 5811 – Transfer Tax
Combinations of Parts
You cannot avoid registration by storing a device in pieces. Under § 5845(f)(3), any set of parts “designed or intended for use in converting any device into a destructive device” counts as the device itself if it could be readily assembled into a working one. Keeping a grenade casing, fuse, and explosive filler in the same location is legally the same as possessing a completed grenade.
What Is Not a Destructive Device
Several categories fall outside the definition, and the exclusions are narrower than people assume.
Sporting shotguns. A standard 12-gauge has a bore around .729 inches, well over the half-inch line, but shotguns and shotgun shells the government finds “generally recognized as particularly suitable for sporting purposes” are exempt.3Office of the Law Revision Counsel. 18 USC 921 – Definitions The exemption depends on that ATF finding; combat-style shotguns without a recognized sporting purpose have been classified as destructive devices.
Sporting rifles over half an inch. A rifle with an oversized bore may qualify for the sporting-purpose exclusion, but recognition is not automatic. The owner submits a written request to ATF under 27 CFR 479.24, signed under penalty of perjury, with photographs or drawings and a description of intended use. ATF can require the actual rifle for examination.4eCFR. 27 CFR 479.24 – Determination of Sporting Purpose
Antiques. Firearms manufactured in or before 1898 are excluded from the NFA’s definition of “firearm” entirely, so a Civil War cannon is not a destructive device.5Bureau of Alcohol, Tobacco, Firearms and Explosives. 27 CFR 478.11 – Meaning of Terms Modern muzzleloading cannon that fire inert solid projectiles with black powder have historically been treated by ATF as devices “not likely to be used as a weapon” under 27 CFR 479.11. That treatment is regulatory, not statutory. Loading explosive shells changes the analysis, and the shells themselves are destructive devices.
Flare guns and signaling devices. These are excluded while they remain in their intended configuration. Pair a flare launcher with sub-caliber inserts that let it fire conventional ammunition and ATF classifies the combination as an “any other weapon” under the NFA, even if the insert is never installed. Merely possessing both items together triggers the classification.6Bureau of Alcohol, Tobacco, Firearms and Explosives. Open Letter to All Federal Firearms Licensees – Flare Inserts
The $200 Tax Still Applies in 2026
Starting January 1, 2026, the NFA making and transfer tax dropped to $0 for suppressors, short-barreled rifles, short-barreled shotguns, and “any other weapons.” Destructive devices and machine guns were deliberately left out of that reduction.2Office of the Law Revision Counsel. 26 USC 5811 – Transfer Tax Every transfer of a destructive device still requires a $200 tax paid by the transferor, and every new device manufactured requires a separate $200 making tax from the maker.7Office of the Law Revision Counsel. 26 USC 5821 – Making Tax If you assume the suppressor process applies to a large-bore firearm or a grenade, your application will be rejected or delayed. The tax is paid by stamp, attached to the original form, before ATF processes the registration.
How to Register, Buy, or Build One
Buying a destructive device from another private owner or a dealer runs on ATF Form 4 (Application for Tax Paid Transfer and Registration of a Firearm), filed in duplicate by the transferor with the $200 tax attached. An individual buyer must include two passport-style photographs taken within the last six months and fingerprint cards on FBI Form FD-258. ATF runs a background check, and the buyer cannot take possession until the transfer is approved.8Bureau of Alcohol, Tobacco, Firearms and Explosives. NFA Handbook Chapter 9 – Transfers of NFA Firearms Approval commonly takes several months. If the transfer would violate any federal, state, or local law, ATF will deny it.
Building your own runs on ATF Form 1 (Application to Make and Register a Firearm) with the same $200 tax, fingerprints, photographs, and background check. Construction cannot begin before ATF approves the form.9Bureau of Alcohol, Tobacco, Firearms and Explosives. ATF Form 5320.1 – Application to Make and Register NFA Firearm Starting assembly early is itself a federal offense under 26 U.S.C. § 5861(f).10Office of the Law Revision Counsel. 26 USC 5861 – Prohibited Acts
Moving, Inheriting, and Storing One
Interstate Transport
Under 18 U.S.C. § 922(a)(4), only licensed importers, manufacturers, dealers, and collectors may move destructive devices across state lines without specific ATF authorization.11Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts Every other owner must file ATF Form 5320.20 in advance.12Bureau of Alcohol, Tobacco, Firearms and Explosives. ATF Form 5320.20 – Application to Transport Interstate or to Temporarily Export Certain NFA Firearms Approval covers only the dates and routes on the form. When a commercial carrier is involved, a copy of the approved form must travel with the shipment.
Inheritance
A registered destructive device can pass to a named heir or someone entitled under state law without the $200 transfer tax, using ATF Form 5 (Application for Tax Exempt Transfer and Registration of a Firearm) with the heir’s fingerprint cards.13Bureau of Alcohol, Tobacco, Firearms and Explosives. ATF Form 5 – Application for Tax Exempt Transfer and Registration of Firearm ATF will still deny the transfer if the heir cannot legally receive the device. The executor cannot hand the device to a dealer for storage or consignment; that movement is itself a transfer requiring paperwork.14Bureau of Alcohol, Tobacco, Firearms and Explosives. Transfers of National Firearms Act Firearms in Decedents’ Estates If the device turns out to be unregistered, it is contraband and cannot be registered after the fact; the only lawful option is surrender to the local ATF field office.
Storage of Explosive Devices
This is where many private owners run aground. Federal explosives regulations in 27 CFR Part 555 apply on top of the NFA, not instead of it.15eCFR. 27 CFR Part 555 – Commerce in Explosives Explosive materials must be kept in approved magazines, locked when not being handled, inspected at least every seven days for tampering, and kept clear of open flames or spark-producing devices within 50 feet.16eCFR. 27 CFR Part 555 Subpart K – Storage The required distance between the magazine and the nearest inhabited building depends on the quantity stored, following the table at 27 CFR § 555.218.17eCFR. 27 CFR 555.218 – Table of Distances for Storage of Explosive Materials Even small quantities demand meaningful separation from any dwelling. Local fire authorities must be notified in writing of the storage location within 48 hours of first storing explosives there. For a homeowner, these setbacks often make compliant storage impossible on a normal residential lot.
Federal Penalties
Any violation of the NFA carries a maximum of 10 years in federal prison, a fine, or both.18Office of the Law Revision Counsel. 26 USC 5871 – Penalties The NFA text caps fines at $10,000, but 18 U.S.C. § 3571 allows fines up to $250,000 for any felony, and NFA offenses are felonies.19Office of the Law Revision Counsel. 18 USC 3571 – Sentence of Fine Any firearm involved is subject to seizure and forfeiture.
The prohibited acts in 26 U.S.C. § 5861 are broad: possessing an unregistered destructive device, receiving one that was made or transferred illegally, transporting an unregistered device in interstate commerce, or making a false statement on any NFA application. There is no mandatory minimum, but explosive ordnance cases tend to draw sentences at the higher end of the range. A conviction also permanently strips the right to possess any firearm under federal law.
State Law Can Override Federal Approval
Federal registration is a floor, not a ceiling. Some states ban private possession of destructive devices outright, some prohibit explosive ordnance while allowing large-bore firearms, and some carve out narrow exceptions only for items on the federal Curio and Relic list. ATF will deny a Form 4 or Form 1 that would put the applicant in violation of state or local law, so checking your state’s rules before starting a registration saves months of processing time on an application that was never going to be approved.