Used only on La Argentina, this was a loose barrel AA gun with a horizontally sliding breech block.
This weapon is described as having a vertically sliding breech block in "Naval Weapons of World War Two" but the photograph below shows quite clearly that it is horizontally sliding.
|Designation||4"/50 (10.2 cm) QF Vickers Armstrong Mark P|
|Ship Class Used On||La Argentina|
|Date Of Design||About 1935|
|Date In Service||1937|
|Gun Weight||2.175 tons (2.210 mt) including BM|
|Gun Length oa||210.75 in (5.353 m)|
|Bore Length||200.0 in (5.080 m)|
|Rifling Length||166.807 in (4.347 m)|
|Grooves||(32) 0.039 x 0.270 in (1.00 x 6.86 mm)|
|Lands||0.123 in (3.12 mm)|
|Twist||Uniform RH 1 in 30|
|Chamber Volume||499.8 in3 (8.19 dm3)|
|Rate Of Fire||10 - 12 rounds per minute (?)|
|Weight of Complete Round||57.75 lbs. (25.2 kg)|
|Projectile Types and Weights||HE: 31 lbs. (14.1 kg)|
|Muzzle Velocity||3,000 fps (914 mps) 1|
|Working Pressure||19.0 tons/in2 (2,990 kg/cm2)|
|Approximate Barrel Life||N/A|
|Ammunition stowage per gun||N/A|
- ^With such a high muzzle velocity, I would suspect that barrel life was rather short.
|45 degrees||19,900 yards (18,200 m)|
|AA Ceiling @ 90 degrees||37,400 feet (11,400 m)|
|Elevation||-5 / +90 degrees|
|Elevation Rate||14 degrees per second 1a|
|Train||About -50 to +50 degrees|
|Train Rate||16 degrees per second 1a|
- ^The elevation and train rate speeds given above assume that RPC was fitted to these mountings, but it is not known if this equipment was actually installed.
- "Naval Weapons of World War Two" by John Campbell
- "Cruisers of World War Two" by M.J. Whitley