This legislative proposal, designated the "Age 21 Act," aims to amend federal law to restrict firearm access for individuals under 21 years of age. Its primary purpose is to prohibit the purchase and possession of specific types of firearms and related accessories by this age group. The bill introduces new definitions and modifies existing provisions within Title 18 of the United States Code. A significant portion of the bill is dedicated to defining the items subject to these new restrictions. It explicitly defines semiautomatic pistols , semiautomatic shotguns , and a broad category of semiautomatic assault weapons . The definition of semiautomatic assault weapons includes rifles, pistols, and shotguns with certain features like detachable magazines, pistol grips, or threaded barrels, and also lists numerous specific firearm models and their variants. Furthermore, the bill defines large capacity ammunition feeding devices as those capable of holding more than 10 rounds, with an exception for .22 caliber rimfire tubular devices. Other defined terms include various firearm components such as barrel shrouds, detachable and fixed ammunition feeding devices, folding stocks, forward grips, grenade launchers, pistol grips, and threaded barrels. These detailed definitions are crucial for identifying the firearms and accessories covered by the prohibitions. The core prohibition prevents individuals under 21 from purchasing or knowingly possessing handguns , semiautomatic assault weapons , large capacity ammunition feeding devices , and ammunition exclusively for these weapons. However, several exceptions are outlined. These include temporary possession or use for employment, ranching, farming, target practice, hunting, or firearm instruction, provided there is prior written parental or guardian consent. Members of the Armed Forces or National Guard are also exempt when acting in the line of duty, as are cases of inheritance of title or possession for self-defense against an intruder in a residence.