[1] It consists of an M242 Bushmaster chain gun mounted on a turret that can be either manually or remote controlled, depending on variant.

[4] The Mark 38 25 mm MGS provides ships with short-range capability against high-speed maneuvering surface targets (HSMSTs),[5] floating mines, and enemy swimmers.

[6] All variants of the Mk 38 require two crewmembers for conducting maintenance (e.g., replacing the Bushmaster in the event it malfunctions, which takes five minutes).

The Bushmaster uses an electric motor to drive the moving parts for ammunition feeding, loading, firing, extraction, and cartridge ejection.

Tests demonstrated that the Mod 2 mounting has a three times greater probability of hit versus previous variants.

The surveillance system can move independently of the turret itself, intended to minimize attention drawn from targets.

[4][3][10][11] In 1977, the U.S. Chief of Naval Operations (CNO) decided that the Oerlikon 20 mm Mk 16 guns would need to be replaced.

The Crane Division of the Naval Surface Warfare Center was responsible for designing and manufacturing the Mark 88 mounting.

The Mod 1s were frequently installed only for temporary durations aboard vessels, rotated among ships based on mission priorities.

The incident led to the recognition of an upgraded Mk 38 MGS as a means to improve shipboard protection against the threat of small surface craft.

[7] On June 8, 2004, United Defense (acquired by BAE Systems) received a $395.5 million contract to produce the Mod 2.

In 2021, MSI-Defence begun delivery of its Seahawk DS30M A2 30 mm gun mount to the USN for testing and qualification for the Mod 4.

[17] The Mk 38 Mod 4 will achieve initial operating capability on Arleigh Burke-class destroyers with Aegis Baseline 9 in FY2022.