Under Ohio law, dangerous ordnance is a defined category of weapons and explosives that the state regulates more tightly than ordinary firearms. Ohio Revised Code 2923.11(K) lists what qualifies: automatic firearms, sawed-off rifles and shotguns, zip-guns, ballistic knives, bombs and incendiary devices, high explosives and blasting agents, military weapons like rocket launchers and grenades, firearm suppressors, and even parts assembled with intent to build any of the above. Possessing any of these items in Ohio without either a federal National Firearms Act registration or an Ohio dangerous ordnance license is a felony.
What Counts as Dangerous Ordnance in Ohio
ORC 2923.11(K) breaks the definition into six subsections. The first covers four kinds of weapons that qualify no matter how they were acquired or how long you’ve owned them.1Ohio Legislative Service Commission. Ohio Code 2923.11 – Weapons Control Definitions
An automatic firearm is any gun that fires more than one round with a single trigger pull. A semi-automatic that has been modified to fire automatically counts the same as a factory-built machine gun.
A sawed-off firearm means a shotgun with a barrel under 18 inches, a rifle with a barrel under 16 inches, or any rifle or shotgun with an overall length under 26 inches. These are precise legal cutoffs. A shotgun barrel at exactly 18 inches is legal; at 17 and seven-eighths, it is dangerous ordnance.
A zip-gun is an improvised firearm built from parts not made by a commercial manufacturer. A ballistic knife has a detachable blade launched by a spring mechanism, which is why Ohio treats it like a short-range firearm rather than an edged weapon.
Subsection (K)(2) picks up explosive and incendiary devices, meaning anything designed to detonate or ignite and cause damage through blast, heat, or fragmentation. The device does not have to work. Possessing one that is designed or intended to function that way is enough.
Subsection (K)(3) regulates the explosive materials themselves, not just finished devices. Named compounds include nitroglycerin, nitrocellulose, TNT, picric acid, PETN, cyclonite, dynamite, blasting gelatin, and sensitized ammonium nitrate, along with composite military explosives such as amatol, tritonal, and pentolite. The list ends with a catch-all for any other explosive with enough brisance or power to be suitable for military use or for mining, quarrying, excavating, or demolitions. A new compound not named in the statute still qualifies if it hits that threshold.
Subsection (K)(4) covers military weapons: rocket launchers, mortars, artillery, grenades, mines, bombs, torpedoes, and the ammunition made for them. The statute keys on whether the weapon was “designed and manufactured for military purposes,” not purely on caliber or bore diameter. A .50-caliber rifle built for the civilian long-range market is treated differently from a .50-caliber military anti-materiel weapon, though items built for military use will usually fall under both Ohio’s definition and the federal “destructive device” definition at the same time.2Office of the Law Revision Counsel. 26 USC 5845 – Definitions
Subsection (K)(5) makes any firearm muffler or suppressor dangerous ordnance in itself, with no exception for size, caliber, or sporting use.
Finally, subsection (K)(6) covers parts intended for conversion. If you possess a collection of components and intend to assemble them into something that would qualify under any of the earlier subsections, the parts themselves are dangerous ordnance. You do not have to finish the build. Prosecutors establish intent through circumstantial evidence such as purchase history, searches, partially completed modifications, or statements to others.
What Ohio Excludes From the Definition
ORC 2923.11(L) carves out seven categories that would otherwise meet the definition but are specifically excluded.1Ohio Legislative Service Commission. Ohio Code 2923.11 – Weapons Control Definitions
Black-powder and obsolete-ignition firearms are excluded regardless of actual age, so a modern reproduction of a cap-and-ball revolver is treated the same as an original. Sporting firearms, including military designs issued or modified for sporting use, are excluded unless they are automatic or sawed-off. This is the exemption that keeps hunting rifles, competition pistols, and sporting shotguns from being swept in.
Also excluded: pre-1887 artillery pieces designed only for black powder and without recoil systems; black powder, primers, and percussion caps used as propellants for exempt firearms; and dangerous ordnance kept as a trophy, souvenir, curio, or museum piece if it is inoperable or inert and cannot readily be made functional again. Items expressly exempt from the federal “destructive device” definition under 18 U.S.C. 921(a)(4) carry their exemption into Ohio law.3Office of the Law Revision Counsel. 18 US Code 921 – Definitions So do firearms with an overall length of at least 26 inches that the ATF has approved for sale under the Gun Control Act but determined are not regulated under the NFA.
Ohio’s antique rule is not the federal one. The federal cutoff is manufacture before 1898; Ohio keys on ignition system and powder type. A cartridge-firing rifle made in 1890 does not qualify for the Ohio exclusion, while a new black-powder percussion-cap gun does.
Who Can Legally Possess It
Possession of dangerous ordnance is unlawful under ORC 2923.17 unless you fall into one of eight exempt categories.4Ohio Legislative Service Commission. Ohio Code 2923.17 – Unlawful Possession of Dangerous Ordnance The exemptions cover government and military personnel acting within their duties; federally licensed explosives importers, manufacturers, dealers, and users under 18 U.S.C. 843; federally licensed destructive-device importers, manufacturers, and dealers under 18 U.S.C. 923; recipients of surplus military ordnance distributed under federal programs; owners of items properly registered in the National Firearms Registration and Transfer Record under 26 U.S.C. 5841; commercial carriers and warehouses handling the items in the ordinary course of business; holders of an Ohio license or temporary permit issued under ORC 2923.18; and hunters using a suppressor attached to a firearm authorized for hunting under Ohio’s wildlife regulations.
For most civilians, two paths matter. The first is NFA registration. Machine guns, short-barreled rifles and shotguns, suppressors, and destructive devices all require registration in the national registry. A properly registered NFA item satisfies the exemption under ORC 2923.17(C)(5). The reverse is not true: an Ohio license on its own does not satisfy federal law.
The second is an Ohio dangerous ordnance license under ORC 2923.18. Applications go to the sheriff of your county or the safety director or police chief of your city.5Ohio Legislative Service Commission. Ohio Revised Code 2923.18 – License or Temporary Permit The application must be in writing and under oath, and it must state your name, age, address, and occupation (or business name and address), describe the specific ordnance you want to possess, explain where and how you plan to store and use it, and give the purpose for acquiring it. The issuing authority can ask for more.
To qualify you must be at least 21, not otherwise prohibited by law from possessing dangerous ordnance, and able to show enough competence to handle the item safely. The issuing authority also looks at your security arrangements and whether your purpose is legitimate. A regular license costs $50 and lasts at least a year, with the authority free to set a longer or indefinite expiration. A temporary permit for one-time or casual use of consumable ordnance such as explosives costs $5 and expires within 30 days.
Penalties for Unlawful Possession
Unlawful possession of dangerous ordnance under ORC 2923.17(A) is a fifth-degree felony.4Ohio Legislative Service Commission. Ohio Code 2923.17 – Unlawful Possession of Dangerous Ordnance6Ohio Legislative Service Commission. Ohio Revised Code 2929.14 – Definite Prison Terms7Ohio Legislative Service Commission. Ohio Revised Code 2929.18 – Financial Sanctions, Felony Illegally manufacturing or processing explosives under ORC 2923.17(B) is a second-degree felony, carrying two to eight years in prison and a fine up to $15,000.
Any dangerous ordnance involved in a violation is subject to seizure. A felony conviction also costs you your firearm rights under both Ohio and federal law, which makes legally owning any firearm afterward effectively impossible without a restoration of rights.
Federal NFA Rules That Also Apply
Most items Ohio treats as dangerous ordnance are also regulated under the federal National Firearms Act, and the federal exposure is often the greater concern. Possessing an unregistered NFA firearm is a federal crime carrying up to 10 years in prison.8Office of the Law Revision Counsel. 26 USC 5871 – Penalties While the NFA caps its own fines at $10,000, a separate federal sentencing provision raises the maximum fine to $250,000 for individuals.9Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). NFA Handbook – Chapter 15: Penalties and Sanctions The firearm itself is subject to seizure and forfeiture.
Transferring an NFA item requires ATF Form 4 and a background check on the buyer. As of January 1, 2026, the federal excise tax on transfers of suppressors, short-barreled rifles, short-barreled shotguns, and “any other weapons” dropped to $0. Machine guns and destructive devices still carry a $200 transfer tax. The tax change does not eliminate the paperwork; registration, background check, fingerprint cards, and passport photos remain mandatory.
When a registered NFA item passes to an heir through an estate, the transfer uses ATF Form 5320.5 and is tax-exempt regardless of item type, including machine guns and destructive devices. The ATF still reviews the transfer against federal, state, and local law, so a beneficiary in a state that bans the item category can be denied.10Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Application to Transfer and Register NFA Firearm – Tax Exempt (ATF Form 5)
Moving a machine gun, short-barreled rifle, short-barreled shotgun, or destructive device across state lines requires advance ATF approval on Form 5320.20, submitted and approved before travel. Suppressors do not require this form for interstate transport.11Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Application to Transport Interstate or Temporarily Export Certain NFA Firearms (ATF Form 5320.20) A single unregistered machine gun can trigger an Ohio fifth-degree felony and a federal charge with a decade in prison at the same time, so compliance has to work on both levels.