Pennsylvania’s law on prohibited offensive weapons, 18 Pa.C.S. § 908, makes it a first-degree misdemeanor to possess, sell, repair, or use any weapon the statute defines as offensive. A conviction can bring up to five years in prison, a $10,000 fine, and a permanent ban on possessing any firearm in the Commonwealth. The statute names specific weapons and adds a catch-all for anything built to cause serious bodily injury with no common lawful purpose. Several defenses exist, but each one places the burden of proof on the person charged.
Weapons the Statute Prohibits
Section 908 defines an “offensive weapon” to include bombs and grenades, machine guns, shotguns with a barrel shorter than 18 inches, any firearm specially made or adapted to be concealed or to fire without a normal report, blackjacks, sandbags, metal knuckles, stun guns, stun batons, tasers, and similar electric devices.1Pennsylvania General Assembly. 18 Pennsylvania Code 908 – Prohibited Offensive Weapons
Short-barreled rifles are not separately listed by name, though a rifle modified for concealment could fall within the concealed-firearm language. They are regulated federally under the National Firearms Act, and the NFA defense discussed below applies to them in Pennsylvania.
After the named items, the definition ends with a catch-all: any implement designed to inflict serious bodily injury and serving no common lawful purpose qualifies. That gives law enforcement room to charge improvised or unconventional weapons that aren’t specifically listed but exist primarily to hurt people.
Where Stun Guns and Tasers Fit
Stun guns, stun batons, and tasers sit inside the Section 908 definition, which surprises people who assume these self-defense tools are freely legal. A separate provision, Section 908.1, carves out a self-defense exception. You may possess and use an electronic incapacitation device to defend yourself or your property, provided the device is labeled with clear instructions about its use and potential for harm.2Pennsylvania General Assembly. Pennsylvania Code Title 18 – Amend Offensive Weapons, Electric or Electronic Incapacitation Devices Law enforcement officers, correctional employees, and members of the National Guard may also carry these devices for official duties.
Most Pennsylvanians can legally carry a properly labeled stun gun or taser under that exception. But the underlying classification still matters. Using one offensively rather than defensively, or carrying one without the required labeling, can trigger a Section 908 charge.
Automatic Knives Are No Longer Prohibited
Until 2022, the statute’s list of offensive weapons included automatic knives, switchblades, and similar bladed instruments that opened by switch, push-button, or spring. Act 119 of 2022 removed that language. These knives are now legal to own and carry in Pennsylvania.1Pennsylvania General Assembly. 18 Pennsylvania Code 908 – Prohibited Offensive Weapons Every other item on the list remains fully prohibited unless a statutory defense applies.
Criminal Penalties
Possessing, selling, repairing, or using a prohibited offensive weapon is a misdemeanor of the first degree, one grade below a felony under Pennsylvania’s criminal classification.1Pennsylvania General Assembly. 18 Pennsylvania Code 908 – Prohibited Offensive Weapons The maximum sentence is five years in prison3Pennsylvania General Assembly. Pennsylvania Code Title 18 – Crimes and Offenses and a $10,000 fine.4Pennsylvania General Assembly. Pennsylvania Code Title 18 Chapter 11 – Authorized Disposition of Offenders
The offense reaches more than simple possession. Repairing a prohibited weapon, selling one, or otherwise dealing in one all trigger the same charge. A gunsmith who works on a sawed-off shotgun without confirming its NFA registration faces the same exposure as the owner.
The Lifetime Firearms Ban
This is the consequence most people don’t see coming. Section 6105 of the Crimes Code lists a Section 908 conviction as a disqualifying offense. If you’re convicted, you lose the right to possess, use, sell, or obtain a license for any firearm in Pennsylvania, permanently.5Pennsylvania State Police. Pennsylvania Code 18 Pa.C.S. Section 6105 – Persons Not to Possess, Use, Manufacture, Control, Sell or Transfer Firearms
A single conviction for carrying metal knuckles or an unlabeled stun gun can cost you your hunting rifles, your home defense handgun, and your concealed carry license. The ban covers all firearms, not just the type of weapon involved in the original offense. For anyone who owns guns or relies on them for work, this collateral consequence outweighs the prison time and the fine.
Defenses Under Section 908
Section 908(b) sets out several affirmative defenses. An affirmative defense means you admit the possession but argue it was lawful, and you carry the burden of proving the defense by a preponderance of the evidence. The prosecution does not have to disprove it.
Curio
You may possess an offensive weapon if you held it solely as a curio. The statute uses that single word. It does not require the item to be antique or ornamental, but “solely” is a high bar. A weapon that is loaded, stored near ammunition, or kept in a way suggesting readiness for use will not survive the curio defense.1Pennsylvania General Assembly. 18 Pennsylvania Code 908 – Prohibited Offensive Weapons The ATF’s federal Curios and Relics classification is a separate legal standard, but a firearm with recognized collector status can strengthen the state-law argument.6ATF. Curios and Relics
Dramatic Performance
Actors, crew, and others involved in theatrical productions, film shoots, or similar performances may possess offensive weapons for use in the performance. The defense covers possession during the production, not indefinite personal ownership justified by occasional stage use.
Found Weapon or Weapon Taken From an Aggressor
Briefly possessing a prohibited weapon because you found it or took it from an attacker is a recognized defense. The key word is “briefly.” It covers a person who disarms an attacker and holds the weapon until police arrive, or who picks up an abandoned device to turn it in. It does not cover someone who found a weapon months ago and kept it at home.3Pennsylvania General Assembly. Pennsylvania Code Title 18 – Crimes and Offenses
Circumstances Negating Unlawful Intent
The statute also allows a defense for circumstances similarly negating any intent or likelihood that the weapon would be used unlawfully. Courts read this narrowly, requiring a context that made unlawful use effectively impossible.
National Firearms Act Compliance
The most practically important defense for firearms owners is NFA compliance. Section 908(b) makes compliance with the National Firearms Act (26 U.S.C. § 5801 et seq.) a defense to a prohibited-weapon charge, with one hard exception: bombs, grenades, and incendiary devices can never be defended on NFA grounds, even if federally registered.
In practice, you can legally possess NFA-regulated items like suppressors, short-barreled shotguns, short-barreled rifles, and machine guns in Pennsylvania once you have completed federal registration, typically on ATF Form 4 for a transfer. Because the NFA defense is affirmative, you should keep the approved registration paperwork with the item or somewhere accessible, so a police contact does not turn into a prolonged legal fight.
Local Governments Cannot Add to the List
Section 6120 of the Crimes Code preempts counties, municipalities, and townships from regulating firearms, ammunition, and related components beyond what state law provides. Philadelphia, Pittsburgh, and every other municipality in the Commonwealth cannot add weapons to the prohibited list or create stricter possession rules than Section 908 already contains. If your possession is legal under state law, a local ordinance cannot make it illegal.