View source for 5-inch/25-caliber gun

{{Short description|20th-century heavy anti-aircraft gun of the U.S. Navy}}
{{Use dmy dates|date=June 2017}}
{{Infobox weapon
|name= 5"/25 Caliber Gun
|image=5 inch 25 caliber gun USS Bowfin.jpg
|image_size=300px
|caption= On the deck of {{sclass|Balao|submarine|1}} {{USS|Bowfin|SS-287|6}}
|origin= United States
|type= [[Anti-aircraft gun]]<br />[[Naval gun]]
<!-- Type selection -->
|is_artillery=yes
<!-- Service history -->
|service=
|used_by= US Navy, [[Argentine Navy]]
|wars= World War II, [[Falklands War]]
<!-- Production history -->
|designer=
|design_date=
|manufacturer=
|production_date=
|number=
|variants= Mk 10, 11, 13, 17
<!-- General specifications -->
|weight= 2 metric tons
|length= 11 ft 10 in (3.6 m)
|part_length= {{convert|10|ft|5|in|mm|abbr=on|sigfig=4}} bore (25 [[Caliber (artillery)|calibers]])<br />8 ft 2 in (2.4 m) rifling
|width=
|height=
|crew=
<!-- Ranged weapon specifications -->
|cartridge=127 × 626&nbsp;mm R fixed or semi-fixed<br>{{convert|52|to|54.5|lb|kg|abbr=on}}<ref>{{Cite web |url=http://www.navweaps.com/Weapons/WNUS_5-25_mk10.htm |title=United States of America 5"/25 (12.7 cm) Marks 10, 11, 13 and 17 |access-date=24 November 2010 |archive-date=12 June 2016 |archive-url=https://web.archive.org/web/20160612023551/http://www.navweaps.com/Weapons/WNUS_5-25_mk10.htm |url-status=live }}</ref>
|caliber= {{convert|5|in|mm|abbr=on|sigfig=3}}
|action=
|rate=
|velocity= 2,100&nbsp;ft/s (640&nbsp;m/s) average
|range={{convert|14500|yd|m}} at 40°<br />{{convert|27400|ft|m}} at 85°
|max_range=
|feed=
|sights=
<!-- Artillery specifications -->
|breech=
|recoil=
|carriage=
|elevation=-10° to +85°
|traverse=
<!-- Explosive specifications -->
|diameter=
|filling=
|filling_weight=
|detonation=
|yield=
}}

The '''5"/25 caliber gun''' (spoken "five-inch-twenty-five-caliber") entered service as the standard heavy [[anti-aircraft]] (AA) gun for United States [[Washington Naval Treaty]] [[cruisers]] commissioned in the 1920s and 1930s. The goal of the 5"/25 design was to produce a heavy AA gun that was light enough to be rapidly trained manually.<ref name="DiGiulian, Tony">{{Cite web |url=http://www.navweaps.com/Weapons/WNUS_5-25_mk10.htm |title=United States of America 5"/25 (12.7 cm) Mark 10 |access-date=2013-08-10 |date=September 2012 |author=DiGiulian, Tony |publisher=navweaps.com. |archive-date=12 June 2016 |archive-url=https://web.archive.org/web/20160612023551/http://www.navweaps.com/Weapons/WNUS_5-25_mk10.htm |url-status=live }}</ref> The gun was also mounted on pre-[[World War II]] [[battleship]]s and [[aircraft carrier]]s until replaced by the standard widespread [[dual-purpose gun|dual-purpose]] [[5"/38 caliber gun]], which was derived from the 5"/25. Guns removed from battleships were probably converted for submarine use by late 1943, while a purpose-built variant for submarines was available in mid-1944, and was widely used by them.<ref name=C137>Campbell 1985 p.137</ref> United States naval gun terminology indicates the gun fired a projectile 5&nbsp;inches (127&nbsp;mm) in diameter, and the barrel was 25 [[Caliber (artillery)|caliber]]s long (that is, for a 5" bore and a barrel length of 25 calibers, 5" x 25 = 125", or about 3.2 meters).<ref name=F156>Fairfield 1921 p.156</ref> It is referred to sometimes as a dual-purpose gun and sometimes as an anti-aircraft gun, because of its comparative weakness against surface targets.

==History==
[[File:127mm gun battery aboard USS New Mexico (BB-40) off Saipan on 15 June 1944.jpg|thumb|left|upright|Battleship {{USS|New Mexico|BB-40|6}}'s 5"/25 battery prepares to fire during the [[Battle of Saipan|bombardment of Saipan]], 15 June 1944]]
The gun weighed about 2 metric tons and used fixed ammunition (case and projectile handled as a single assembled unit) with a 9.6-pound (4.4&nbsp;kg) charge of [[smokeless powder]] to give a 54-pound (24&nbsp;kg) projectile a velocity of 2100 feet per second (640&nbsp;m/s). The ceiling was {{convert|27400|ft}} at the maximum elevation of 85 degrees.  Useful life expectancy was 4260 [[List of British ordnance terms#Effective Full Charge|effective full charge]]s (EFC) per barrel.<ref name=C137 /> The short barrel of the 5"/25 made it much easier to train manually against fast-moving targets. These guns were manually controlled so the short barrel and light weight made it an early favorite as an anti-aircraft gun. Another key feature was power loading, allowing rapid fire at high elevation angles. The [[5"/38 caliber gun]] replaced the 5"/25 as the anti-aircraft weapon of choice on new construction by the mid-1930s due to its better range, velocity against surface targets, and higher vertical ceiling. The 5"/38 was effectively a compromise between the shorter-barreled 5"/25 (intended primarily for air targets) and the longer-barreled [[5-inch/51-caliber gun]] (intended primarily for surface targets) in order to create a highly-effective [[dual-purpose gun|dual-purpose]] naval gun.

5"/25 guns removed from pre-war battleships (especially those rebuilt after [[Attack on Pearl Harbor|Pearl Harbor]]) had their barrel linings chromed. These guns were remounted for submarine use beginning in late 1943 for extra firepower against small boats and [[sampan]]s often encountered off the coast of Japan and elsewhere in the Pacific Theater, replacing the earlier [[3"/50 caliber gun|3-inch]] and [[4"/50 caliber gun|4-inch]] guns. New production Mark 17 5"/25 guns on the Mark 40 mount designed for submarines became available in mid-1944; {{USS|Spadefish|SS-411|6}} was the first submarine built with this gun. Some submarines had two of these weapons.<ref name="DiGiulian, Tony"/> The Mark 17 gun in the Mark 40 submarine gun mount may have used [[Shell (projectile)#Separate loading cased charge|semi-fixed]] ammunition (case and projectile handled separately), but existing WW II photographs, drawings of ammunition storage, and museum ships all show fixed ammunition (one piece service round). It had a range of {{convert|14500|yd}} at the maximum elevation of 40 degrees.<ref name=C138>Campbell 1985 p.138</ref> The submarine mounting had manual elevation, train, and loading with no power assist.

From late 1944 some submarines were built or refitted with two of these weapons. The first of these was {{USS|Sennet|SS-408|6}}, commissioned on 22 August 1944. In February–March 1945 she operated with two other two-gun submarines, {{USS|Haddock|SS-231|6}} and {{USS|Lagarto|SS-371|6}}, in a [[wolfpack (naval tactic)|wolfpack]] with significant success.<ref name=FriedSubs1>Friedman 1995, pp. 218-219</ref> To further improve the effectiveness of the two-gun configuration, seven submarines were fitted with a Mark 6 "[[Mark I Fire Control Computer|Baby Ford]]" [[fire-control system|fire control]] computer with a Mark 6 stable element to correct for pitch and roll.<ref>{{Cite web |url=http://www.glennsmuseum.com/bombsights/mk6.html |title=Mark 6 computer at Glenn's Computer Museum |access-date=5 March 2017 |archive-date=17 June 2016 |archive-url=https://web.archive.org/web/20160617091553/http://www.glennsmuseum.com/bombsights/mk6.html |url-status=live }}</ref><ref>{{Cite web |url=https://maritime.org/doc/stablemk6/index.htm |title=Mark 6 stable element manual |access-date=5 March 2017 |archive-date=23 December 2016 |archive-url=https://web.archive.org/web/20161223171330/http://www.maritime.org/doc/stablemk6/index.htm |url-status=live }}</ref> The first of these was {{USS|Sea Cat|SS-399|6}}, followed by {{USS|Flying Fish|SS-229|2}}, {{USS|Entemedor|SS-340|2}}, {{USS|Sea Dog|SS-401|2}}, {{USS|Sea Poacher|SS-406|2}}, {{USS|Sea Robin|SS-407|2}}, and ''Sennet''. However, some of these refits were completed in September 1945, too late to see action.<ref name=FriedSubs1/>

==Ships mounting 5"/25 caliber guns==

(all heavy and light cruisers in the list are "[[Washington Naval Treaty|treaty cruisers]]")

(none of the heavy cruisers appear to ever have had their secondary battery upgraded, despite quite a few having been heavily damaged and extensively repaired).

The heavy cruiser {{USS|Wichita|CA-45|2}} (ca. 1935), the last 2 of the {{sclass|Brooklyn|cruiser|0}} light cruisers (ca. 1937), the {{sclass|North Carolina|battleship|4}} of battleships (ca. 1937) and the {{sclass|Yorktown|aircraft carrier|0}} aircraft carriers (ca. 1934) were originally built with the more modern 5-inch/38 guns.

* 2 {{sclass|Pensacola|cruiser|0}} (ca. 1927) heavy cruisers:<ref name=F9>Fahey 1941 p.9</ref>
** {{USS|Pensacola|CA-24|2}}, {{USS|Salt Lake City|CA-25|2}}
*** two each port and starboard of the forward superstructure
*** two each port and starboard of the aft superstructure<ref name="ONI_222-US">Office of Naval Intelligence, ONI 222-US</ref>
* 6 {{sclass|Northampton|cruiser|0}} (ca. 1928) heavy cruisers:<ref name=F9/>
** {{USS|Northampton|CA-26|2}}, {{USS|Chester|CA-27|2}}, {{USS|Louisville|CA-28|2}}, {{USS|Chicago|CA-29|2}}, {{USS|Houston|CA-30|2}}, {{USS|Augusta|CA-31|2}}
*** four each port and starboard of the aft superstructure<ref name="ONI_222-US"/>
*** originally built with 4 guns and later upgraded

* 2 {{sclass|Portland|cruiser|0}} (ca. 1930) heavy cruisers:<ref name=F9 />
** {{USS|Portland|CA-33|2}}, {{USS|Indianapolis|CA-35|2}}
*** same layout as Northampton<ref name="ONI_222-US"/>
* 7 {{sclass|New Orleans|cruiser|0}} (ca. 1931) heavy cruisers:<ref name=F9 />
** {{USS|New Orleans|CA-32|2}}, {{USS|Astoria|CA-34|2}}, {{USS|Minneapolis|CA-36|2}}, {{USS|Tuscaloosa|CA-37|2}}, {{USS|San Francisco|CA-38|2}}, {{USS|Quincy|CA-39|2}}, {{USS|Vincennes|CA-44|2}}
*** four each port and starboard of the forward superstructure extending past the stacks<ref name="ONI_222-US"/>

* 7 of 9 {{sclass|Brooklyn|cruiser|0}} (ca. 1935) light cruisers:<ref name=F9 />
** {{USS|Brooklyn|CL-40|2}}, {{USS|Philadelphia|CL-41|2}}, {{USS|Savannah|CL-42|2}}, {{USS|Nashville|CL-43|2}}, {{USS|Phoenix|CL-46|2}}, {{USS|Boise|CL-47|2}}, {{USS|Honolulu|CL-48|2}}
*** four each side adjacent to the forward superstructure extending past the stacks<ref name="ONI_222-US"/>
*** ''Savannah'' and ''Honolulu'' secondary battery was later upgraded<ref name=C137/>
*** 2 of 9, ''St. Louis'' and ''Helena'' (ca. 1937), originally built with 5-inch/38 gun mounts.

* 2 {{sclass|Lexington|aircraft carrier|0}} (ca. 1921 - 1925) aircraft carriers:
** {{USS|Lexington|CV-2|2}},<ref name=F390>Friedman 1983 p.390</ref> {{USS|Saratoga|CV-3|2}}<ref name=F390 />
*** 6 per side
*** replaced with 5-inch/38 guns by May 1942 on ''Saratoga'' during a [[Japanese submarine I-6|surprise]] visit to the drydock
*** still on ''Lexington'' when [[Battle of the Coral Sea|sunk in May 1942]]

* {{USS|Ranger|CV-4|2}} (ca. 1931)<ref name=F391>Friedman 1983 p.391</ref>
** originally built with 8 guns

* 2 {{sclass|Nevada|battleship|0}} battleships:
** {{USS|Nevada|BB-36|2}},<ref name=B210>Breyer 1973 p.210</ref> {{USS|Oklahoma|BB-37|2}}<ref name=B210 />
*** 8 installed in 1927-1930 refits
*** replaced with 5-inch/38 guns on ''Nevada'' in 1942

* 2 {{sclass|Pennsylvania|battleship|0}} battleships:
** {{USS|Pennsylvania|BB-38|2}},<ref name=B214>Breyer 1973 p.214</ref> {{USS|Arizona|BB-39|2}}<ref name=B214 />
*** 8 installed in 1929 refit
*** replaced with 5-inch/38 guns on ''Pennsylvania'' in 1942

* 3 {{sclass|New Mexico|battleship|0}} battleships:
** {{USS|New Mexico|BB-40|2}},<ref name=B219>Breyer 1973 p.219</ref> {{USS|Mississippi|BB-41|2}},<ref name=B219 /> {{USS|Idaho|BB-42|2}}<ref name=B219 />
*** 8 installed in early 1930 modernization
*** replaced with 5-inch/38 guns on ''Idaho'' in 1942
*** still on ''New Mexico'' and ''Mississippi'' at the end of the war<ref name=C137/>

* 2 {{sclass|Tennessee|battleship|0}} battleships:
** {{USS|Tennessee|BB-43|2}},<ref name=B226>Breyer 1973 p.226</ref> {{USS|California|BB-44|2}}<ref name=B226 />
*** 8 installed in 1928-1930 refits
*** replaced with 5-inch/38 guns in 1942

* 3 {{sclass|Colorado|battleship|0}} battleships:
** {{USS|Colorado|BB-45|2}},<ref name=B230>Breyer 1973 p.230</ref> {{USS|Maryland|BB-46|2}},<ref name=B230 /> {{USS|West Virginia|BB-48|2}}<ref name=B230 />
*** 8 installed in 1928-1930 modernization
*** replaced with 5-inch/38 guns in 1942 on ''Maryland''<ref>ONI 222-US says no replacement was done, photos of the ship look like there are no /38 turrets</ref> and ''West Virginia''
*** still on ''Colorado'' at the end of the war<ref name=C137/>

*{{sclass|Gato|submarine}}s<ref name=C138 /> (as a typical upgrade)
*{{sclass|Balao|submarine}}s<ref name=C138 /> (standard)
*{{sclass|Tench|submarine}}s<ref name=C138 /> (standard)

==See also==
* [[Deck gun]]
{{clear}}

==Notes==
{{Reflist|30em}}

==References==
* {{cite book|title=Battleships and Battle Cruisers 1905–1970|author=Breyer, Siegfried|publisher=Doubleday and Company|year=1973|isbn=978-0-385-07247-2}}
* {{cite book|title=Naval Weapons of World War Two|author=Campbell, John|publisher=Naval Institute Press|year=1985|isbn=0-87021-459-4}}
* {{cite book|title=The Ships and Aircraft of the U.S. Fleet, Two-Ocean Fleet Edition|author=Fahey, James C.|author-link=James Charles Fahey|publisher=Ships and Aircraft|year=1941}}
* {{cite book|title=Naval Ordnance|author=Fairfield, A.P.|publisher=The Lord Baltimore Press|year=1921}}
* {{cite book|title=U.S. Aircraft Carriers|author=Friedman, Norman|publisher=Naval Institute Press|year=1983|isbn=0-87021-739-9}}
* {{cite book |last=Friedman|first=Norman |title=U.S. Submarines Through 1945: An Illustrated Design History |publisher=[[United States Naval Institute]] |year=1995|location=[[Annapolis, Maryland]] |isbn=1-55750-263-3}}
* {{cite book|title=U.S. Warships of World War II|author=Silverstone, Paul H.|publisher=Ian Allan Ltd|year=1965}}

==External links==
{{Commons category}}
* [http://maritime.org/doc/fiveinch25 5-INCH GUN MOUNT MARK 40, OP 1029, 1944. Manual for submarine gun & mounting] Made available online by maritime.org

{{WWIIUSNavalWeapons}}

{{DEFAULTSORT:5 25 Caliber Gun (United States)}}
[[Category:World War II naval weapons]]
[[Category:Naval guns of the United States]]
[[Category:127 mm artillery]]
[[Category:Naval anti-aircraft guns]]
[[Category:Military equipment introduced in the 1920s]]