Firearms and Ammunition - As introduced, prohibits the purchase or possession of a firearm by a person 18 or older but less than 25 if the person was previously adjudicated delinquent for an act that, if committed by an adult, would have constituted certain offenses; allows the TBI access to juvenile court records for the limited purpose of performing certain background checks prior to the purchase or transfer of a firearm. - Amends TCA Title 18; Title 37 and Title 39.