You don't have to be a circus performer of magician to own throwing knives, but many states impose restrictions on these and other kinds of weapons. Laws can vary widely, ranging from making throwing knives outright illegal to being unclear on what is allowed. If you own or are considering buying throwing knives, you should first research your state laws and find out what is or isn't allowed.
Some states specifically outlaw throwing knives or similar weapons. For example, Texas outlaws illegal knives. Texas Penal Code § 46.01 defines, in part, an illegal knife as any hand instrument that is designed to either cut or stab another person by being thrown. Further, it defines a knife as any bladed hand instrument capable of inflicting serious damage, injury or death either through cutting or stabbing.
Other states, such as Florida, do not specifically state that throwing knives are illegal, but place limits on what people can carry. For example, Florida Statutes § 790.01 and § 790.001 restrict people from carrying concealed weapons. The only exceptions are for "the common pocket knife."
Other states impose restrictions on knives, including throwing knives. These restrictions can limits knives based on the knife's blade length, attributes or by a person's age.
For example, the New York Penal Article 265.01 makes it illegal to own any "switchblade" knife or "gravity" knife. Further, 265.05 makes it illegal for anyone under the age of 16 to possess any "dangerous knife."
In addition to state laws governing the ownership and use of throwing knives, there are also federal laws that can apply. U.S. Code § 1241 bans anyone but manufacturers from transporting switchblade and gravity knives through interstate commerce.
Further, the sale or transportation of ballistic knives is also prohibited. Ballistic knives are defined as any knife with a detachable blade that can throw or project the blade through a spring-operated mechanism.