Assault Weapons Ban of 2019 This bill makes it a crime to knowingly import, sell, manufacture, transfer, or possess a semiautomatic assault weapon (SAW) or large capacity ammunition feeding device (LCAFD). The prohibition does not apply to a firearm that is (1) manually operated by bolt, pump, lever, or slide action; (2) permanently inoperable; (3) an antique; or (4) a rifle or shotgun specifically identified by make and model. The bill also exempts from the prohibition the following, with respect to a SAW or LCAFD: importation, sale, manufacture, transfer, or possession related to certain law enforcement efforts, or authorized tests or experiments; importation, sale, transfer, or possession related to securing nuclear materials; and possession by a retired law enforcement officer. The bill permits continued possession, sale, or transfer of a grandfathered SAW, which must be securely stored. A licensed gun dealer must conduct a background check prior to the sale or transfer of a grandfathered SAW between private parties. The bill permits continued possession of, but prohibits sale or transfer of, a grandfathered LCAFD. Newly manufactured LCAFDs must display serial number identification. Newly manufactured SAWs and LCAFDs must display the date of manufacture. The bill also allows a state or local government to use Edward Byrne Memorial Justice Assistance Grant Program funds to compensate individuals who surrender a SAW or LCAFD under a buy-back program.