ATLANTIC OCEAN (June 1, 2021) The Arleigh Burke-class guided-missile destroyer USS Paul Ignatius (DDG 117) fires an MK-45 MOD 4 5-inch 62 caliber lightweight gun as part of a live-fire exercise during exercise At-Sea Demo/Formidable Shield, June 1, 2021. Exercise At-Sea Demo/Formidable Shield, conducted by Naval Striking and Support Forces NATO on behalf of U.S. 6th Fleet, is a live-fire integrated air and missile defense (IAMD) exercise that improves Allied interoperability using NATO command and control reporting structures. (U.S. Navy photo by Mass Communication Specialist 2nd Class Nathan T. Beard)