Britain
6"/50 (15.2 cm) BL Marks XI and XI*
Updated 11 February 2012
Introduced on HMS Black Prince in 1906 and subsequently used as secondary guns on many pre-dreadnoughts.  These were the first 6" (15.2 cm) guns of 50 calibers to be mounted on a European ship.  These guns were found to be too heavy to aim manually, especially on the smaller cruisers.  For that reason, hydraulic power gear was added to some mounts in the latter part of World War I.

During World War II, these guns were used on auxiliary warships, armed liners, DEMS and Ocean Boarding Vessels.  They were also extensively used in Australian coast defenses constructed prior to World War II.

Constructed of a tapered inner A tube, A tube, wire, full length jacket, breech ring and breech bush screwing into the A tube.  Mark XI* differed in having a thicker inner A tube and the use of cannelured rings at the two forward shoulders.  A total of 177 were built, which were 34 Mark XI, 18 Mark XI*, 124 Mark XI* with a slightly different breech ring for PVI mountings and one "H" Mark XI* which was a Coventry ordnance gun with Holmstrom breech mechanism.  This last gun was linered down to 3 inches (7.62 cm) and used for experimental purposes.  Of the remainder, 126 remained in service as of 1939.  Twenty-six Mark XI guns were used in Australian coastal batteries prior to World War II and many others were used in emergency coastal defense batteries during the war.  At least one Australian and two South African guns still survive, as can be seen on the additional pictures page.
WNBR_6-50_mk11_Newcastle.jpg

HMS Newcastle in 1918 showing stern and broadside 6" (15.2 cm) guns
IWM Photograph
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Click here for additional pictures
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Gun Characteristics
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Designation 6"/50 (15.2 cm) BL Mark XI and XI*
Ship Class Used On Last three King Edward VII class

Duke of Edinburgh, Bristol, Falmouth and Chatham cruiser classes

Monitor Marshal Ney
Date Of Design 1905
Date In Service 1906
Gun Weight 19,237 lbs. (8,726 kg)
Gun Length oa 309.7 in (7.867 m)
Bore Length 300.0 in (7.620 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume 2,030 in3 (33.27 dm3)
Rate Of Fire
(see Note)		 5 - 7 rounds per minute
Note:  The Rate of Fire figure given above is found in references for British guns of this caliber, but "Warrior to Dreadnought:  Warship Development, 1860-1905" quotes Jellicoe's 1906 figures for rates of fire for these guns in gunlayers' tests and in battle practice and notes that the latter figures corresponded well to those actually attained by the Japanese at Tsushima:

Gunlayers Test:  12 rounds per minute
Battle Practice:  4 rounds per minute

In "Jutland:  An Analysis of the Fighting" by John Campbell, it is stated that almost all British capital ships had few or slow hoists for their 6" (15.2 cm) guns and that once the ready ammunition was used up, the rate of fire dropped to about 3 rounds per minute.  For light cruisers the rate of supply was was about three to five rounds per minute per gun and usually closer to the lower figure.
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Ammunition
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Type Bag
Projectile Types and Weights CPBC - 100 lbs. (45.36 kg)
CPC 2crh - 100 lbs. (45.3 kg)
CPC 4crh - 100 lbs. (45.3 kg)
HE 4crh - 100 lbs. (45.3 kg)
Bursting Charge CPC 4crh - 7.5 lbs. (3.4 kg)
HE 4crh - 13.3 lbs. (6.0 kg)
Projectile Length CPC 4crh - 23.5 in (59.7 cm)
HE 4crh - 22.9 in (58.2 cm)
Propellant Charge 32.1 lbs. (14.6 kg) MD26
33.1 lbs. (15 kg) SC150
Muzzle Velocity 2,937 fps (895 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun Pre-dreadnoughts:  200 rounds
Cruisers:  N/A
Marshal Ney:  100 rounds
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Range
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Elevation With 100 lbs. (45.36) HE Shell
Range @ 13 degrees 11,200 yards (10,240 m)
Range @ 15 degrees 14,310 yards (13,085 m)
Note:  During the Falklands Battle of 1914, these 6" (15.2 cm) guns on HMS Glasgow were reported to have been badly outranged by the much smaller German 10.5 cm (4.1") guns on SMS Leipzig.  However, the heavier British shells with their lyddite bursters were significantly more effective than the lighter German ones.
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Armor Penetration with 2crh 100 lbs. (45.4 kg) CPC Projectile
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Range Vertical KC Plate
3,000 yards (2,740 m) 3.0 in (7.6 cm)
Note:  Data from "The Grand Fleet:  Warship Design and Development 1906-1922" for an angle of obliquity of 30 degrees and a striking velocity of 1,502 fps (458 mps).  Projectiles were salt-filled (blind).
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Armor Penetration with 4crh 100 lbs. (45.4 kg) CPC Projectile
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Range Vertical KC Plate
3,000 yards (2,740 m) 3.5 in (8.9 cm)
Note:  Data from "The Grand Fleet:  Warship Design and Development 1906-1922" for an angle of obliquity of 30 degrees and a striking velocity of 1,746 fps (532 mps).  Projectiles were salt-filled (blind).
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Mount / Turret Data
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Designation Single Mounts
   King Edward VII (10) and Duke of Edinburgh (10):  PV
   Bristol (2):  PV*
   Falmouth (8) and Chatham (8):  PVI
   Marshal Ney (6):  PV
Weight (less shield) N/A
Elevation PV and PV*:  -7 / +13, later +20 degrees on some

PVI:  -7 / +15 degrees
Elevation Rate Manual operation, only
Train about +150 / -150 degrees
Train Rate Manual operation, only
Gun recoil N/A
Notes:

1) Marshal Ney was given guns from the scrapped HMS Hibernia.

2) PV and PV* mountings were made by Elswick while the PVI mountings were made by Coventry Ordnance Works.
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Data from
"Warrior to Dreadnought:  Warship Development 1860-1905" and "The Grand Fleet:  Warship Design and Development 1906-1922" both by D.K. Brown
"Big Gun Monitors:  The History of the Design, Construction and Operation of the Royal Navy's Monitors" by Ian Buxton
"Jutland:  An Analysis of the Fighting", "Naval Weapons of World War Two" and "British Naval Guns 1880-1945 No 11" article in "Warship Volume VII" all by John Campbell
"Cruisers of the Royal and Commonwealth Navies" by Douglas Morris
"British Battleships:  1860 - 1950" by Oscar Parkes
"Graf Spee's Raiders:  Challenge to the Royal Navy, 1914-1915" by Keith Yates
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"The Mavens' Word of the Day" by Random House Books
Page History

07 January 2007 - Benchmark
11 February 2012 - Updated to latest template