Overview of 18 Pa. C.S.A. § 908—Prohibited Offensive Weapons
Pennsylvania law strictly regulates certain weapons considered especially dangerous or lacking legitimate everyday use. Under Title 18 Pa. C.S.A. § 908 (Prohibited offensive weapons), it is generally illegal to possess, use, manufacture, repair, sell, or transfer these items.
In the article below, our gun and weapons crime lawyer breaks down the law.
What Qualifies as a “Prohibited Offensive Weapon”?
Title 18 Pa. C.S.A. § 908 includes both specifically named weapons and a broader category of items that may be considered illegal based on how they function.
Explosive Devices (Bombs, Grenades)
Bombs, grenades, and similar devices designed to explode and inflict serious bodily injury or cause property damage are prohibited.
Common fireworks, such as firecrackers or bottle rockets, are not automatically considered prohibited offensive weapons because they have a recognized recreational purpose and are regulated separately. However, the line is crossed when a firework is modified, combined, or constructed in a way that turns it into a destructive device.
There is no specific size or explosive-weight threshold in § 908 itself. Instead, courts look at whether the device is functionally a weapon, meaning it can cause serious harm. However, explosive materials are regulated under federal law (18 U.S.C. Chapter 40) depending on how they are manufactured, stored, or used.
Machine Guns
A machine gun is a firearm that can fire multiple rounds automatically with a single pull of the trigger. This prohibition does not apply to semi-automatic weapons, which fire one round per trigger pull.
This classification also applies to firearms that have been modified or converted to fire fully automatic. In those cases, law enforcement may rely on testing or expert analysis to determine how the weapon operates.
Sawed-Off Shotguns
Sawed-off shotguns are prohibited since they are easier to conceal and more dangerous at close range. Pennsylvania law (18 Pa. C.S.A. § 6102) looks at the weapon’s dimensions to determine whether it qualifies:
- Barrel length: Typically, less than 18 inches
- Overall length: Typically, less than 26 inches
If a shotgun falls below these thresholds, it is classified as a prohibited weapon, regardless of whether it was originally manufactured that way or was modified after purchase, such as cutting down the barrel or stock.
Law enforcement will physically measure the firearm, and those measurements are used to determine whether the weapon meets the statutory definition.
Firearm Silencers (Suppressors)
Firearm silencers, also known as suppressors, are devices attached to the barrel of a firearm to reduce the sound, flash, and recoil of a gunshot. They are prohibited based on their function.
There is no size or measurement requirement for a silencer. However, silencers are regulated under the National Firearms Act. Individuals may lawfully possess a suppressor if they obtain the federal “tax stamp,” register the device, and comply with all applicable requirements.
Even then, compliance with federal law does not automatically eliminate potential issues under Pennsylvania law, and how the device is classified can still depend on the specific facts of the case.
Switchblade Knives
Switchblade knives are generally understood to be knives with a blade that opens automatically by pressing a button, spring, or similar mechanism built into the handle. The defining feature is instant, automatic deployment, not the size or shape of the blade.
Pennsylvania law does not provide a detailed technical definition within § 908, so courts and law enforcement focus on how the knife operates:
- Automatic knives (switchblades): Blade opens instantly by pressing a button or mechanism in the handle
- Spring-assisted knives: Blade requires manual pressure on the blade before a spring assists in opening
- Manual folding knives: Blade opens only through manual effort
Whether a knife qualifies often depends on whether it opens fully automatically or requires some level of manual initiation.
Metal Knuckles (Brass Knuckles)
Metal knuckles, commonly known as brass knuckles, are worn over the fingers and concentrate the force of a punch into a smaller, harder surface, increasing the likelihood of serious injury. Unlike some other weapons, their classification is based on purpose and design, not size or measurement:
Since these devices are specifically designed to cause harm during physical contact, they are generally treated as per se prohibited, meaning they are automatically prohibited based on what they are rather than something evaluated under a “common lawful purpose” analysis.
In practice, law enforcement and courts look at how the object is constructed and whether it functions as a striking aid. Even if an item is marketed under a different name or incorporates additional features, it may still fall within this category if it serves the same core purpose.
Daggers and Certain Concealed Blades
Daggers and similar blades are typically defined as knives with a double-edged blade designed primarily for stabbing. Concealed or disguised blades are items hidden within another object (e.g., cane swords or pen knives designed to conceal a blade).
These blades are often designed for combat or surprise use, distinguishing them from common tools like kitchen knives or folding pocketknives. Also, there is no specific blade length that automatically makes a knife illegal.
Unlike switchblades, which are evaluated based on their opening mechanism, daggers and concealed blades are analyzed more closely under the “no common lawful purpose” standard. Courts look at the blade’s design, how it is carried, and the surrounding circumstances to determine whether it qualifies as a prohibited offensive weapon.
The Catch-All Category: “No Common Lawful Purpose”
One of the most important and misunderstood parts of 18 Pa. C.S.A. § 908 is,
“Any other implement for the infliction of serious bodily injury which serves no common lawful purpose.”
This provision is designed to cover items that may not be named but are clearly intended to function as weapons rather than tools.
There is no bright-line test for this category, meaning the law does not provide a fixed rule, such as a specific size, weight, or feature, that automatically makes an item illegal.
In practice, this determination is made through a fact-specific analysis. Law enforcement may initiate charges, prosecutors decide how to pursue the case, and the courts consider whether the object has any legitimate everyday use or whether it is primarily associated with causing harm.
Are There Exceptions Under 18 Pa. C.S.A. § 908?
Under 18 Pa. C.S.A. § 908(b), certain limited exceptions may apply. These can include:
- Law enforcement and military use in the course of official duties
- Curiosities or collectibles, such as antique weapons kept for display
- Educational or scientific purposes, where the item is used in a controlled setting
These exceptions are narrow and fact-specific. A person claiming an exception may need to demonstrate that their situation clearly fits within the law. Our criminal defense attorney can explain more.
What Are the Penalties for Violating § 908?
A violation is typically graded as a misdemeanor of the first degree. Potential consequences may include:
- Up to five years of incarceration
- Fines
- A permanent criminal record
The exact outcome may depend on the type of weapon involved, the circumstances of the possession, and a person’s prior record
Call McKenzie Law Firm, P.C. for Help With Prohibited Weapon Charges
If you are facing charges involving a prohibited offensive weapon, contact McKenzie Law Firm, P.C. You can call to discuss your situation, get clear answers about your options, and take the next step forward.
