What defines the legal length of a rifle barrel?

The legal length of a rifle barrel is defined as being more than 16 inches. This specification is established under the National Firearms Act (NFA) and is essential for categorizing firearms in the United States. A rifle is legally classified as such only if its barrel exceeds this length, meaning that any firearm with a barrel 16 inches or shorter would be considered an "illegal" firearm or categorized differently, such as a short-barreled rifle (SBR). This distinction is significant for legal ownership, regulation, and the application of laws governing the use and possession of firearms. Understanding this legal definition is crucial for both law enforcement and individuals handling firearms to ensure compliance with federal regulations.