The "Gas-Operated Semi-Automatic Firearms Exclusion Act," or GOSAFE Act, aims to significantly restrict the availability of certain firearms and ammunition feeding devices. It broadly defines a "gas-operated semi-automatic firearm" to include any firearm that uses gas, recoil, or blowback energy to cycle its action, firing one cartridge per trigger pull. Additionally, the bill defines "large capacity ammunition feeding devices" as those capable of holding more than 10 rounds, excluding .22 caliber rimfire ammunition. The legislation makes it unlawful to import, sell, manufacture, transfer, receive, or possess these defined firearms and devices, as well as parts designed to convert non-prohibited firearms into prohibited ones or devices that materially increase a firearm's rate of fire. While existing, lawfully manufactured gas-operated semi-automatic firearms are **grandfathered**, their transfer is restricted to immediate family members only, requiring a licensed dealer to facilitate the background check. Exceptions to these prohibitions are provided for government agencies and certain licensees under the Atomic Energy Act for security purposes. A key provision establishes a federal process for the Attorney General, through the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), to publish and regularly update a list of prohibited gas-operated semi-automatic firearms. Any new semi-automatic firearm designs intended for civilian sale must undergo an approval process by the Attorney General to ensure they are not subject to the prohibitions. To fund these regulatory activities, a new **Firearm Safety Trust Fund** is established, which will receive fees from the approval process and existing National Firearms Act taxes. Violations of the prohibitions carry penalties including fines up to $5,000 and up to 12 months imprisonment per offense. Committing another federal felony while possessing a prohibited gas-operated semi-automatic firearm incurs additional, more severe penalties, including substantial fines and longer prison terms. Furthermore, the bill amends existing law to allow Byrne grants to be used for state and local **buy-back programs** for these newly restricted firearms and large capacity ammunition feeding devices.