Chile
4"/62 (10.2 cm) Vickers Mark Q
Updated 14 August 2010
An interesting automatic weapon that grew out of the cancelled British 5" (12.7 cm) projects of the 1940s and 1950s.

The original plan was to use surplus 4"/45 (10.2 cm) Mark XVI guns in an automatic mounting similar to the mountings that Vickers was designing for the 5" (12.7 cm) post-war projects.  Later, the gun was changed to a design similar to a high-powered anti-aircraft gun being used by the British Army.  This mounting was to be used for rearming the Argentine training cruiser La Argentina and also for Peruvian and Chilean warships.  None of these plans were proceeded with, but then in the mid-1950s Vickers and the Chilean navy struck a deal whereby a new 4" (10.2 cm) mounting would be used on two destroyers to be built by Vickers.

This gun loads though the trunnions with the breech forward of them, an unusual design feature that made it somewhat easier to load the gun at any angle of elevation.  The Director of Naval Ordnance (DNO) was skeptical of this arrangement, as it was argued that this would make for a greater inertia in the rotating mass, hence for slower elevation and train.  Vickers response was that this through-trunnion scheme had actually originated with the 2-pdr Mark M mounting, widely used during the war and considered a fairly successful weapon.

Constructed of an autofretted loose barrel, jacket breech ring and vertical sliding breech mechanism.  The rammer was pneumatic with alternate left and right loading trays fed from left and right hoppers.
WNARG_4-62_Vickers_Almirante_Riveros_pic.jpg

Almirante Riveros
Photograph copyrighted by Vickers
WNCHL_4-62_Vickers_right_pic.jpg

4"/62 (102 mm) mounting now at Museo de Cañones Navales in Bahia de Valparaíso, Chile
Photograph copyrighted by Carlos Mey and used here by his kind permission
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Gun Characteristics
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Designation 4"/62 (10.2 cm) Vickers
Ship Class Used On Almirante Riveros (DD-18)
Date Of Design 1957
Date In Service 1960
Gun Weight Gun with BM:  3.116 tons (3.166 mt)
Loose barrel:  1.066 tons (1.083 mt)
Gun Length oa 258.0 in (6.553 m)
Bore Length 248.0 in (6.292 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire 50 rounds per minute maximum
40 rounds per minute practical
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Ammunition
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Type Fixed
Weight of Complete Round N/A
Projectile Types and Weights
(see Note)		 HE - 32 lbs. (14.5 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge 14.813 lbs. (6.7 kg) N/S 198-054
Muzzle Velocity 2,953 fps (900 mps)
Working Pressure 17.5 tons/in2 (2,759 kg/cm2)
Approximate Barrel Life N/A
Ammunition stowage per gun
(see Note)		 N/A
Note:  Projectile weight above from "The Naval Institute Guide to World Naval Weapon Systems 1991/92.  "British Naval Guns 1880-1945 No 18" says that the projectiles weighed 35 lbs. (15.9 kg).
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Range
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Elevation With 23 lbs. (10.4 kg) HE Shell
Maximum Surface Range 20,230 yards(18,500 m)
Maximum AA Altitude about 39,400 feet (12,000 m)
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Mount / Turret Data
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Designation Single Mounts
   Almirante Riveros (4):  Vickers Universal Mount
Weight  47,040 lbs. (21,337 kg)
Elevation -7 / +85 degrees
Elevation Rate N/A
Train about +150 / -150 degrees
Train Rate N/A
Gun recoil N/A
Loading Angle Any angle
Notes:

1) This mounting was electrically powered with a gyro sight and joystick for local control.  Control cabin was located on the right side of the mounting.  Gun house normally had seven crewmembers.

2) The guns fed from two 28-round hoppers located between the trunnions.  New rounds could be fed into the hoppers while the guns fired.
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Data from
"British Naval Guns 1880-1945 No 18" article by John Campbell in "Warship Volume X"
"The Naval Institute Guide to World Naval Weapon Systems 1991/92" by Norman Friedman
"Vanguard to Trident:  British Naval Policy since World War Two" by Eric J. Grove
Page History

05 April 2008 - Benchmark
14 August 2010 - Corrected projectile weight and added note regarding same