Coast Guard service members with Port Security Unit 301 load ammunition into a .50 caliber M2HB machine gun from a fixed battle position during a Field Training Exercise in the Port of Tampa Bay on Monday, March 11, 2019. PSUs conduct critical missions capable of protecting ports and waterways within the U.S. and supporting expeditionary operations overseas. U.S. Coast Guard photo by Petty Officer 1st Class Sara Romero.