If you’ve ever thought about carrying brass knuckles in Missouri (or already have them), you might want to think again. Brass knuckles are illegal in Missouri — and getting caught with them could lead to criminal charges.
But there’s a twist. The Constitutional law and criminal defense experts at James Law Group argue this ban violates your rights under the Second Amendment.
Let’s break down what Missouri law says, why it may be unconstitutional, and what it means for you.
What Are Brass Knuckles?
Brass knuckles are hard metal weapons (they aren’t all actually brass) worn over your fingers. They’re designed to make your punches stronger and cause exponentially more damage in a “fist” fight. Many also include spikes, blades, or other features, though those features do not change the issues being discussed here.
While they were a common weapon given to troops in WWI (usually attached to a knife), are often shown in movies, and have been around since at least the 12th century, Missouri law takes them very seriously.
Missouri Revised Statutes § 571.020
Despite their ready availability to purchase on-line and in other many other states, Missouri law bans the possession, sale, and use of brass knuckles. This law makes it a class A misdemeanor to knowingly carry or use a “knuckle weapon.” A “class A misdemeanor” is punishable by up to one year in jail and/or up to a $2,000 fine.
Perhaps as damaging as the potential punishments, a conviction related to the possession of brass knuckles results in a conviction for the possession of an illegal weapon. When people see the charge, they are likely to think you possessed a bazooka or machine gun.
But Wait — What About the Second Amendment?
That’s the big question. The Second Amendment to the U.S. Constitution says:
“A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms shall not be infringed.”
Modern Supreme Court interpretations of the Second Amendment changed dramatically in 2008, when the Supreme Court determined that the Second Amendment protects an individual’s right to carry a firearm. Court decisions and state laws are still dealing with the massive legal shift in legal interpretation of a citizen’s rights to bear arms.
In the 2022 case N.Y. State Rifle & Pistol Ass’n v. Bruen, the Court ruled that a weapon was “in common use” and not “dangerous and unusual,” at the time the Constitution was created, then it is protected by the Constitution. Bruen and other cases have left it less than clear how weapons that were not around in colonial America fit into that analysis, although they do make clear that weapons not present in colonial America (like semi-automatic handguns) are protected by the Second Amendment.
There is little to no evidence that brass knuckles were present or in common use in colonial America, despite their presence in much of the world at that time. They became common place in America during the Civil War, with the first attempts to outlaw them following shortly thereafter. Most state laws banning them in American states, however, were not passed into law until the 20th century.
Why Missouri’s Ban on Brass Knuckles Might Be Unconstitutional
Here are three arguments lawyers are making against Missouri’s brass knuckle ban:
1. Brass knuckles are common
Although they may not have been widely used in colonial America, they were in common use within 50 years of the Constitution’s ratification. There were not immediately outlawed or considered exceptionally dangerous. “Concealed weapons” were often prohibited in early America, and still can pass Constitutional muster (which is why many states still can require a concealed carry permit to carry a concealed weapon).
In no sense of the word could brass knuckles be seen as “uncommon” in America. As of 2025 only 21 states have laws completely prohibiting the possession of brass knuckles. Put another way, they are can be legally possessed in the majority of the United States. They can be purchased at reputable on-line dealers with ease and almost anywhere in states where it is lawful to own them.
2. They’re not “dangerous and unusual”
While bans on machine guns or nuclear weapons likely pass Constitutional muster because the weapons are “dangerous and unusual,” the Supreme Court has specifically found that tasers and stun guns are protected under the Second Amendment. The Court emphasized that for a weapon to fall outside of the Second Amendment’s protections, the weapon must be both particularly dangerous and unusual. A stun gun or taser was found to be neither.
Various lower court decisions applying the tests outlined by the Supreme Court are rife with cherry-picked reasoning and historical examples of regulation or the lack of regulation. The outcome of challenges to specific laws implicating the Second Amendment is still largely unpredictable.
That said, it would appear difficult to argue that brass knuckles are remotely as dangerous as modern firearms that are protected by the Second Amendment. The supreme court made clear that if a weapon is not particularly dangerous, that alone is enough to give it the protections of the Second Amendment.
Moreover, as described above, brass knuckles are hardly rare in American society. The trend in the country is less regulation of these weapons and legalization of them in states like Texas. By almost any measure, they are more common than auto-reset rapid fire triggers or bump-stocks. Other firearms lawfully sold in the United States seem much more “unusual” than brass knuckles, such as a pistol that can shoot .410 shot gun shells or .45 rounds like the Taurus Judge.
3. The ban doesn’t fit historical tradition
One of the factors courts look at when determining if a law restricting ownership or use of weapons is the historical tradition in the United States for similar restrictions. Here is one area where lower courts seem to find whatever examples they want to fit the outcome they believe should occur.
Perhaps the most commonly discussed historical example discussed by courts are the restrictions and bans on the possession or use of Bowie knives that swept the country in the 1850s. The knife had exploded in popularity based on the reputation of and stories about Jim Bowie. Between it’s popularity and pistols of the time being inaccurate and largely unreliable, Bowie knives became a common weapon used in bars, street brawls, and other types of crime. In response, they were heavily regulated.
While this history is often cited as historical evidence of weapon regulation, it is also true that only 2-3 of the relevant laws and regulations actually purported to outlaw the possession of the knives altogether. Most commonly, the restrictions were based on the weapon being concealed. While brass knuckles may be easy to conceal, Missouri’s law does not prohibit concealing the weapon. It prohibits the ownership and mere possession of them.
What Could Happen Next?
These arguments are largely untested in regards to brass knuckles specifically. In March of 2025, an appellate court in Michigan upheld that state’s ban on brass knuckles. Presumably an appeal to a higher court is pending but not resolved at the time of writing.
It is generally unsurprising that lower level courts will not attempt to change settled law. There are no cases anywhere in the country even addressing the issue specifically in the context of brass knuckles. The tests and decisions of the Supreme Court over the last two decades strongly suggests that the Supreme Court would reject such bans, however. Should the Michigan case – or a similar case – ultimately make its way to the Supreme Court, we may see all such bans in the country struck down as unconstitutional.
It is also possible that Missouri, like Texas, will change its law prior to the issue being specifically decided by the Supreme Court. While it may never happen at all, a clear shift in the law feels like it is on the horizon.
What Should You Do?
Don’t carry brass knuckles in Missouri right now. The law still makes it a crime and you will be prosecuted. You can challenge the law’s Constitutionality, but you will be tried, convicted, and sentenced before you can appeal. You may have a lower court that rejects the claim like the Michigan Court did. Even the Supreme Court may ultimately uphold such bans. Of course, regardless of the outcome, you will likely have paid several small fortunes trying to appeal your case to the Supreme Court if the only defense is the law’s Constitutionality.
If you’ve been charged, contact a criminal defense attorney immediately. Make sure you take care in choosing the right attorney who is capable of defending the case.
Watch for legal changes. If courts strike the law down, it could open the door for law-abiding citizens to carry brass knuckles legally for self-defense.
Final Thoughts
Brass knuckles are illegal in Missouri — for now. But that law may not survive much longer. The Second Amendment protects your right to self-defense, and more courts are starting to agree that weapons like brass knuckles deserve protection too.
Whether it’s your right to free speech, your right to be free from unreasonable or unreasonably violent arrest, your right to self-defense or your right to bear arms, James Law Group, LLC is here to protect your most important legal interests.