Modifying a firearm’s barrel length is a regulated activity under the National Firearms Act (NFA) in the United States. A rifle barrel shorter than 16 inches, or a shotgun barrel shorter than 18 inches, creates a “short-barreled rifle” (SBR) or “short-barreled shotgun” (SBS), respectively. These are legally considered distinct firearms and require registration with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), along with payment of a tax, prior to modification. Creating such a firearm without proper authorization is a federal offense.
Barrel length restrictions are in place due to concerns about concealability and potential misuse. Historically, short-barreled firearms were associated with criminal activity, leading to regulations aimed at controlling their proliferation. The NFA’s framework seeks to balance the rights of lawful firearm owners with the need for public safety. Understanding these regulations is crucial for responsible firearm ownership and modification. Legal compliance ensures adherence to the law and avoids potential criminal penalties.