Netherlands
15 cm/50 (5.9") Marks 9, 10 and 11
Updated 29 August 2006
These appear to have been Wilton-Fijenoord versions of the Bofors 15 cm Mark 6.  Marks 9 and 11 were for twin mounts while the Mark 10 was for single mountings.  All these guns used horizontal sliding breech-blocks and had similar ballistics.  Surviving ships were supplied with British-built munitions during World War II.

Actual bore diameter was 14.91 cm (5.87").
WNNeth_59-50_mk9_Tromp_pic.jpg

Light Cruiser RNN Tromp
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Gun Characteristics
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Designation 15 cm/50 (5.9") Marks 9, 10 and 11
Ship Class Used On De Ruyter:  Marks 9 and 10
Tromp:  Mark 11
Date Of Design about 1935
Date In Service 1938
Gun Weight 7.38 tons (7.5 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 - 6 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)
British charges:  35 lbs. (15.9 kg)
Cartridge - 57.7 lbs. (26.2 kg)
Muzzle Velocity AP - 2,953 fps (900 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun
(see Note)		 Tromp:  about 330 rounds
Others:  N/A
Note:  The ammunition stowage per is given in "Cruisers of World War Two" as being 2,000 rounds, but I suspect that this is an error, with this figure actually being the total ammunition outfit.
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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)
Range @ 45 degrees about 30,000 yards (27,400 m)
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Mount / Turret Data
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Designation Single Mount
   De Ruyter (1):  Mark 10

Twin Mounts
   De Ruyter (3):  Mark 9
   Tromp (3):  Mark 11
Weight  N/A
Elevation -10 / +60 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
and
Tony DiGiulian's personal data files