Updated 14 January 2011

5"/25 (12.7 cm) Mark 10 on USS New Mexico BB-40 in 1944
Note the fuze-setting machine on the left and the markings around the gun tub which were to permit quicker training in response to verbal instructions

USS Pennsylvania BB-38 in 1942
The gun shields on the 5"/25 (12.7 cm) weapons was a unique feature of the Pacific Fleet battleships
Note the Mark 19 AA director just forward of the stack
USN Photograph courtesy of NavSource

USS Astoria CA-34
Crew of 5"/25 (12.7 cm) gun # 3 (2nd gun from forward, starboard side) in action during gunnery practice, circa spring 1942.  Note anti-flash head-dress and communications gear worn by the man operating the fuze setter; bearing markings on the gun's splinter shield; and old-style battle helmets.
U.S. Naval Historical Center Photograph # 80-G-21946

Installing a 5"/25 (12.7 cm) Mark 17 on an unidentified US Submarine
Compare the recoil gear on this submarine mounting with the "dry" mountings above

Sketch of wet-mount 5"/25 (12.7 cm) Mark 40 Mod 0

"Gunboat" submarines with two 5"/25 (12.7 cm) guns and centralized fire control
The submarine closest to the picture appears to be USS Sennet (SS-408)

Cutaway sketch of 5"/25 (12.7 cm) ammunition

12 August 2007 - Benchmark
14 January 2011 - Added cutaway sketch