The rule outlines the factors ATF would consider when evaluating firearms equipped with a purported “stabilizing brace” (or other rearward attachment) to determine whether these weapons would be considered a “rifle” or “short-barreled rifle” under the Gun Control Act of 1968, or a “rifle” or “firearm” subject to regulation under the National Firearms Act. The final rule’s amended definition of “rifle” clarifies that the term “designed, redesigned, made or remade, and intended to be fired from the shoulder” includes a weapon that is equipped with an accessory, component, or other rearward attachment (e.g., a “stabilizing brace”) that provides surface area that allows the weapon to be fired from the shoulder, provided other factors, as listed in the definition, indicate the weapon is designed and intended to be fired from the shoulder.