Netherlands
15 cm/50 (5.9") Marks 6, 7 and 8
Updated 16 June 2012
These guns were all manufactured by Bofors and used by the Netherlands Navy on cruisers and sloops (gunboats) built during the 1920s.  It is not clear what were the differences between these different Mark numbers, although I suspect that it had to do with the mountings.  All of these guns used horizontal sliding breech-blocks and had similar ballistics.  Surviving ships were supplied with British-built munitions during World War II.  The sloops Flores and Soemba were intensively used during the invasions of Italy and had their worn-out guns replaced with ones removed from the cruiser Sumatra.

Actual bore diameter was 14.91 cm (5.87").
WNNeth_59-50_mk6_Java_pic.jpg

Light Cruiser RNN Java
Photograph from Allan C. Green collection of glass negatives
State Library of Victoria Image H91.325/284
WNNeth_59-50_mk6_Java_model_pic.jpg

Model of RNN Java
Note that this was a triple-screw warship
National Park Service WAPA Photograph No. 58 Dutchvessle.jpg
WNNeth_59-50_mk6_Flores_pic.jpg

Sloop RNN Flores
Royal Netherlands Navy Photograph
WNNeth_59-50_mk6_Flores_broadsides_pic.jpg

RNN Flores pre-war in Australian waters
Photograph from Allan C. Green collection of glass negatives
State Library of Victoria Image H91.325/272
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Gun Characteristics
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Designation 15 cm/50 (5.9") Marks 6, 7 and 8
Ship Class Used On Mark 6:  Java class
Mark 7:  Flores class
Mark 8:  Johan Maurits van Nassau
Date Of Design 1924
Date In Service 1925
Gun Weight 7.13 tons (7.24 mt)
Gun Length oa about 310.8 in (7.895 m)
Bore Length about 293.5 in (7.455 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire 5 rounds per minute
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Ammunition
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Type Separate
Projectile Types and Weights AP - 103 lbs. (46.7 kg)
HE - 101.4 lbs. (46.0 kg)
British AP - 99.8 lbs. (45.3 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge Dutch charges:  36.8 lbs. (16.7 kg)
Cartridge - 57.7 lbs. (26.2 kg)
British charges:  35 lbs. (15.9 kg)
Muzzle Velocity AP - 2,953 fps (900 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun N/A
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Range
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Elevation With 103 lbs. (46.7 kg) AP
Range @ 29 degrees 23,200 yards (21,214 m)
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Mount / Turret Data
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Designation Single, open-back mounts
   Java (10) and Sloops (3)
Weight 20.0 tons (20.35 mt)
Elevation -10 / +29 or +30 degrees
Elevation Rate N/A
Train about +150 / -150 degrees
Train Rate N/A
Gun recoil N/A
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Data from
"Naval Weapons of World War Two" by John Campbell
"Cruisers of World War Two" by M.J. Whitley
"Warship Pictorial:  The Royal Netherlands Navy 1945-86" article in"Warships Volume X"
Page History

03 December 2008 - Benchmark
16 June 2012 - Redid picture of RNN Java and added picture of Flores