While the right to keep and bear arms is constitutionally protected, all states and the federal government limit a person's ability to carry or possess some kinds of weapons at all, and restrict other weapons in certain situations. Anyone who possesses a weapon that's specifically banned by state or federal law can be charged with a crime like possessing a prohibited weapon.
This article covers what kinds of weapons are illegal and who is banned from possessing some kinds of weapons. The law also forbids weapon possession in certain places and circumstances not covered here. For more information, see our page on gun laws.
Each state and the federal government ban certain kinds of weapons. Though federal law deals mainly with firearms, states often restrict many other categories of weapons.
Federal laws restrict people from possessing certain kinds of firearms. The definition of "firearms" under federal law includes not only guns, but silencers, gun frames or receivers (often used to make ghost guns), and destructive devices (such as bombs and grenades).
Under federal law, people can't possess:
Federal law also bans possession of stolen or armor-piercing ammunition. And it prohibits the sale or transfer of destructive devices, short-barreled shotguns, and short-barreled rifles.
(18 U.S.C. §§ 921, 922 (2022); 26 U.S.C. 5845, 5861 (2022).)
State laws typically prohibit a variety of types of weapons. Though these laws vary from state to state, they often ban or restrict things like explosives, gas guns, switchblade knives, exploding projectiles, brass knuckles, and any weapon prohibited under federal law. States also usually have their own gun registration and permit laws.
In addition to banning particular types of weapons, federal law bans certain people from having otherwise legal firearms, including:
(The limitation on juveniles applies only to handguns and handgun ammunition, and there are exceptions to it, such as inheriting a gun or possessing it for hunting or target practice.)
(18 U.S.C. § 922 (2022).)
Many states have similar rules that overlap with the list above. And some states add to the list.
For example, some states don't allow people under 21 to have handguns. And in states with red flag laws, courts can prohibit people from possessing guns upon finding that they pose a serious danger of gun violence. In that circumstance, the court will issue an order banning the person from owning a gun for a certain period of time.
The crime of unlawful weapon possession is usually proved by establishing two elements: possession and knowledge. In other words, the government must prove that the person had an illegal weapon and knew they had it.
You don't have to hold or carry a weapon to possess it. Having one in your home, or keeping one in your vehicle or somewhere else where you can go and get it is usually enough.
To prove possession, a prosecutor only needs to show that you had control or dominion (authority) over the weapon. So, if you had a gun in a storage locker miles away, you'd still possess it if you could gain access to (or had a right to access) the locker.
Often, it's fairly easy to prove that someone knew they were possessing a weapon. Prosecutors typically rely on circumstantial evidence to prove knowledge because there's often no direct evidence of what's in someone's mind. When an illegal weapon turns up, people don't often announce, "This gun is mine."
Normally, someone having a gun in their car, in their home, or on their person is pretty strong circumstantial evidence that they knew about the weapon. The theory is that most people don't have guns in these places without knowing it.
But sometimes knowledge isn't so clear-cut. For instance, if someone lent their car to a friend who left a gun in the console, the person wouldn't necessarily know that a gun was in their car. Or in a roommate situation, if a gun was under a sofa cushion in the living room, it might not be so clear that a particular roommate knew about the gun.
Under some unusual circumstances, the government might have to prove not only that the person knew about the weapon but also that they knew the type of weapon they had was illegal. For example, if a gun in no way appeared to be a machine gun but turned out to be one, the prosecutor might have to show that the person knew the gun was a machine gun when they possessed it. Importantly, though, the prosecutor wouldn't have to prove that the person knew machine guns are illegal. (Normally, ignorance of the law isn't an excuse.)
(Staples v. United States, 511 U.S. 600 (1994).)
Criminal possession of a weapon is similar to but different from the crime of carrying a concealed weapon.
Sometimes it's illegal for a person simply to have a gun or other weapon. Other times it's not illegal for them to have it, but it's illegal for them to carry it in a particular way (hidden from view). Other times still, it's illegal for them to have it in the first place and the way they carry it is illegal.
With mere weapon possession, it doesn't matter if you're holding the weapon or if, instead, it's in a shoebox at the back of your closet. You can be charged for just having the weapon or having control over it (such as in the storage locker example above).
Depending on the state and the circumstances (for example, people sometimes have permits), you can be charged with carrying a concealed weapon if you have a weapon on you (or immediately accessible to you) that's concealed from view. Concealing a weapon—as by keeping it in your pocket or under the driver's seat of your car—can lead to a charge of this potentially more serious offense.
Some items that are legal to possess (such as kitchen knives) can become illegal when they're concealed. For example, in California, a "dirk or dagger" is prohibited only if it's concealed on the person.
(Cal. Penal Code §§ 16590, 21310 (2022).)
Laws that ban specific types of weapons often include exceptions that allow people to possess them in certain situations. For example, some laws allow museums and educational institutions to display otherwise prohibited weapons. Other laws let people use explosives for industrial or commercial purposes (like mining, for example). And, of course, some kinds of guns can be lawfully possessed depending on state law—for instance, if the person has a permit.
Possessing a prohibited weapon is often charged as a misdemeanor, though in some situations, it can be a felony. In many jurisdictions (the state or federal court a case is in), the dividing line between a misdemeanor and a felony is whether the person has a prior conviction for the same crime or a prior felony.
The sentence for possessing a prohibited weapon can vary widely from case to case. It can lead to one or more of the following:
While being charged with possessing a prohibited weapon might seem like a minor offense, it's almost always in your best interest to speak to an experienced criminal defense attorney whenever you face a criminal charge.
Even if you believe you're not guilty and can't be convicted, the law can be complicated; an attorney with a lot of legal experience might see things about your case that aren't immediately apparent. When you're up against the power of the government trying to take away or limit your freedom, it's important to have a good lawyer on your side.