Byrna launchers are legal to own in Hawaii because they are not firearms under state law, but Hawaii still regulates how you carry and use them. The device runs on compressed CO2 rather than an explosive charge, so it falls outside Hawaii’s firearm permit and registration system. That exemption is narrower than it looks. Concealed carry can be charged as a dangerous weapon offense, chemical projectiles sit in an unresolved legal gray area, and self-defense rules apply the moment you pull the trigger. Here is what the Hawaii laws governing Byrna ownership actually require.
Why a Byrna Is Not a Firearm Under Hawaii Law
Hawaii defines a firearm as a weapon whose operating force is an explosive.1Bureau of Alcohol, Tobacco, Firearms and Explosives. Hawaii State Laws and Published Ordinances – Firearms Ammunition and Dangerous Weapons That covers pistols, revolvers, rifles, and shotguns that fire a projectile with gunpowder or combustion. A Byrna uses compressed CO2, so it does not meet the definition. You do not need a permit to buy one, you do not register it with your county police department, and the firearm-specific provisions of Chapter 134 do not apply to the launcher itself.
That exemption only covers the firearm-specific rules. Other weapon statutes still reach a Byrna depending on the circumstances, and treating the device as unregulated because it is not a firearm is how people end up charged.
Concealed Carry and the Dangerous Weapon Statute
The statute to pay attention to is HRS § 134-51. Knowingly carrying concealed on your person or in a bag any deadly or dangerous weapon is a misdemeanor.2FindLaw. Hawaii Code 134-51 – Deadly or Dangerous Weapons Prohibitions Penalty The statute names specific items like daggers, blackjacks, and metal knuckles, then adds a catch-all for “other deadly or dangerous weapon.” A Byrna firing kinetic or chemical rounds can fit that catch-all depending on how police and prosecutors read the situation.
The exposure escalates with context. Concealed carry alone is a misdemeanor, punishable by up to one year in jail.3Justia Law. Hawaii Code 706-663 – Sentence of Imprisonment for Misdemeanor and Petty Misdemeanor Possessing or using the weapon during another crime is a Class C felony carrying up to five years in prison.4Justia Law. Hawaii Code 706-660 – Sentence of Imprisonment for Class B and C Felonies That second tier is what catches people off guard. If an altercation turns into a harassment or assault charge and you had a Byrna on you, the felony under § 134-51(b) can be stacked on top of the underlying offense.2FindLaw. Hawaii Code 134-51 – Deadly or Dangerous Weapons Prohibitions Penalty
Section 134-51 explicitly excludes firearms, switchblades, butterfly knives, and electric guns because each has its own section of Chapter 134.2FindLaw. Hawaii Code 134-51 – Deadly or Dangerous Weapons Prohibitions Penalty CO2-powered launchers are not carved out anywhere, so the catch-all is the framework most likely to apply.
Chemical Rounds and the Pepper Ball Gray Area
Hawaii permits traditional pepper spray canisters for self-defense, but the statutes do not address pepper ball projectiles fired from a launcher. Law enforcement officials in the state have publicly acknowledged the gap, noting that the law authorizes pepper spray but says nothing about pepper balls. Whether a Byrna round that bursts on impact counts as pepper spray under the self-defense exception, or something else, is unresolved and Hawaii courts have not settled it.
That ambiguity is the single biggest risk for anyone buying chemical rounds. You could carry OC-filled projectiles believing they fall under the pepper spray allowance and still face a prosecutor arguing they do not.
Kinetic-only rounds (hard plastic with no chemical payload) sidestep the chemical question. They still raise the dangerous weapon issue under § 134-51 depending on how you use them, but you avoid the unsettled pepper ball dispute.
County rules add another layer. Honolulu County imposes capacity limits on self-defense sprays and requires sellers to be licensed. Kauai County has its own ordinance regulating pellet guns, setting an age floor of 18 and restricting discharge in public areas and across property lines. Check your specific county before you buy.
Who Cannot Own a Byrna
HRS § 134-7 prohibits certain people from owning, possessing, or controlling any firearm or ammunition. The list includes anyone convicted of a felony, a crime of violence, a firearms offense, or illegal drug distribution. It also covers people under treatment for substance addiction, those acquitted of a crime by reason of mental disease, and those who have been involuntarily hospitalized.5Justia Law. Hawaii Code 134-7 – Ownership Possession or Control Prohibited When Penalty
By its own terms, § 134-7 applies to “firearm or ammunition.”5Justia Law. Hawaii Code 134-7 – Ownership Possession or Control Prohibited When Penalty Because a Byrna is not a firearm under § 134-1, this prohibition may not technically extend to it. Prosecutors have broad discretion, though, and a person in a prohibited category carrying a device that looks and functions like a handgun can face charges under other statutes, including § 134-51.
Hawaii requires you to be at least 21 to acquire a handgun through the permit process.6Hawaiʻi Police Department. Firearm Services For non-firearm self-defense devices, the state sets no uniform minimum age, but Byrna’s own policy requires buyers to be at least 18, and county ordinances may impose their own floors.
When You Can Actually Use It
Owning a Byrna is one question. Firing it at someone is where the real exposure sits. HRS § 703-304 justifies the use of force when you believe it is immediately necessary to protect yourself against unlawful force on the present occasion.7Justia Law. Hawaii Code 703-304 – Use of Force in Self-Protection
For non-deadly force, which is what a Byrna is designed to deliver, subsection (3) lets you estimate the necessity of protective force without retreating as long as you believe the circumstances warrant it.7Justia Law. Hawaii Code 703-304 – Use of Force in Self-Protection You are not required to run before firing a non-lethal round at someone actively threatening you.
Deadly force is different. Hawaii requires retreat if you can do so with complete safety, with one major exception: you are not obligated to retreat from your own home or workplace.7Justia Law. Hawaii Code 703-304 – Use of Force in Self-Protection A Byrna is marketed as non-lethal. If a kinetic round hits someone in the head and kills them, that label will not control how the prosecutor classifies the force. The deadly force rules then apply to what you did.
Two elements have to hold up. You must have genuinely believed the threat was real and force was necessary, and a reasonable person in your position must have believed the same. Firing during a road rage incident, an argument with a neighbor, or as a warning shot does not qualify. The threat must be immediate and the force proportional.
Places Where Carrying Is Restricted
Hawaii limits where weapons can be present even if you own them legally. HRS § 134-9.1 prohibits licensed firearm carriers from bringing weapons into specific locations, and while the statute is written for firearms, the places it identifies are where any weapon draws the most scrutiny:8Justia Law. Hawaii Code 134-9.1 – Carrying or Possessing a Firearm in Certain Locations and Premises Prohibited Penalty
- State and county government buildings, courthouses, and legislative facilities, including their parking areas.
- Public and private schools, charter schools, preschools, and child care facilities.
- Public and private college and university campuses, including buildings, athletic venues, and adjacent parking.
Bringing a Byrna into any of these places risks arrest regardless of whether § 134-9.1 reaches non-firearms directly, because § 134-51’s concealed dangerous weapon prohibition operates independently. A courthouse security officer who finds a launcher in your bag is not going to parse the distinction before calling police.
When you move a Byrna between locations, keep it unloaded and stored in a closed case. Walking through a public area with a launcher holstered on your belt, even if narrowly legal, invites a police encounter and a possible disorderly conduct charge if bystanders report feeling threatened.
Buying, Shipping, and Flying
CO2 cartridges and chemical projectiles are classified as hazardous materials under federal shipping regulations, which limits how carriers can transport them.9eCFR. 49 CFR Part 173 – Shippers General Requirements for Shipments and Packagings Many carriers restrict these items to ground shipping, which to Hawaii means a cargo vessel rather than air freight. Expect longer delivery times and higher costs than mainland orders. Some online retailers decline to ship chemical rounds to Hawaii at all. A local dealer who already handles the hazmat logistics and knows the county rules is usually the most reliable route. The burden of confirming that your specific projectiles comply with Hawaii and county law falls on you, not the seller.
If you are flying, TSA rules apply. Byrna launchers cannot go in carry-on luggage. For checked baggage, TSA allows one container of pepper spray up to 4 fluid ounces with a safety mechanism to prevent accidental discharge. Sprays containing more than 2 percent tear gas by mass are banned from checked bags entirely.10Transportation Security Administration. Pepper Spray CO2 cartridges face additional hazardous materials scrutiny, and individual airline policies vary. Call your airline before packing launcher components.