US Navy destroyer USS Frank E. Petersen Jr. has fired its Mark 45 5-inch main gun during a live-fire exercise while operating in the US 7th Fleet area, according to the US Navy.
The Arleigh Burke-class guided-missile destroyer carried out the firing on 23 September while underway on what the service described as routine operations. Imagery released by the Navy shows the ship’s forward gun being fired over open water.
USS Frank E. Petersen Jr., designated DDG 121, is one of the newer Flight IIA Arleigh Burke-class destroyers in US service. The ship’s Mark 45 naval gun is mounted forward of the bridge and provides the destroyer with a conventional surface-fire capability alongside its missile armament.
The 5-inch weapon can be used against surface targets and for naval gunfire support, while also providing a means of engaging some airborne threats depending on the ammunition and fire-control arrangement being used.
The live-fire event formed part of training intended to maintain proficiency with one of the destroyer’s principal gun systems. US Navy surface combatants routinely conduct live-fire exercises during deployments to test weapons, crews and fire-control procedures under operational conditions. USS Frank E. Petersen Jr. is currently operating within the US 7th Fleet area of operations, which covers much of the western Pacific and Indian Ocean. The fleet is the US Navy’s largest forward-deployed numbered fleet and regularly operates alongside allied and partner navies across the Indo-Pacific.
According to information released with imagery, units assigned to 7th Fleet conduct continuous patrols intended to deter aggression, strengthen alliances and partnerships, and maintain a sustained American naval presence across the region.
The Arleigh Burke class is built around the Aegis combat system and carries a large vertical launch system for surface-to-air, anti-submarine and land-attack missiles. The ships also carry torpedoes, close-in defensive weapons and embarked helicopters, giving them the ability to conduct several missions during a single deployment.
Despite the emphasis placed on missiles aboard modern destroyers, the main gun remains an important part of the ship’s weapons fit. It provides commanders with an alternative to guided weapons for certain surface engagements and can support forces operating ashore where naval gunfire is required.
USS Frank E. Petersen Jr. was named for Lieutenant General Frank E. Petersen Jr., the first African-American Marine Corps aviator and the first African-American Marine Corps general officer. The destroyer entered US Navy service in 2022.
The vessel is homeported at Joint Base Pearl Harbor-Hickam in Hawaii and has since operated across the Indo-Pacific as part of the US Navy’s forward presence in the region.
