Britain
6-pdr / 10cwt [2.244"/47 (57 mm)] QF Mark I
Updated 15 December 2013
These were coast defense guns developed by the Army for use against German Schnellboots ("E-boats") and other small craft.  Twenty-two of them were transferred to the Navy and used on old destroyers detailed for coastal escort duties.

Constructed of A tube, part length jacket and breech ring.  Used a semi-automatic sliding breech block.
WNBR_6pounder_10cwt_m1_Montrose_pic.jpg

HMS Montrose, with twin 6-pdr mount replacing bow 4.7" (12 cm) gun
WNBR_6pounder_10cwt_m1_Mackay_side_pic.jpg

Side view of twin 6-pdr on HMS Mackay
IWM photograph A 18740
WNBR_6pounder_10cwt_m1_Makay_rear_pic.jpg

Loading drill on HMS Mackay
IWM photograph A 20313
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Gun Characteristics
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Designation 6-pdr / 10cwt QF Mark I
Ship Class Used On Campbell, Mackay, Montrose, Whitshed, Wivern, Worcester, Walpole and Windsor
Date Of Design N/A
Date In Service 1941 in naval service
Gun Weight 1,060 lbs. (481 kg)
Gun Length oa 109.7 in (2.787 m)
Bore Length 105.5 in (2.679 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume 73.5 in3 (1.2 dm3)
Rate Of Fire 18 rounds per minute
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Ammunition
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Type Fixed
Weight of Complete Round N/A
Projectile Types and Weights HE - 6.28 lbs. (2.85 kg)
HE-T - 6.54 lbs. (2.97 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge 1.27 lbs. (0.576 kg) N 045
Muzzle Velocity HE - 2,386 fps (727 mps)
HE-T - 2,356 fps (718 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun N/A
Note:  Outfits were half HE and half HE-T (tracer).
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Range
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World War I With 6.28 lbs. (2.85 kg) HE Shell
Range @ 45 degrees 11,300 yards (10,330 m)
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Mount / Turret Data
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Designation Twin Mounts
  Coastal Defense:  Mark I
  Destroyers (1):  Mark I*
Weight  N/A
Elevation -10 / +80 degrees
Elevation Rate Manually operated, only
Train 360 degrees
Train Rate Manually operated, only
Gun recoil 12 in (30.5 cm)
Note:  The naval mounting had a more extensive shield than did the coast defense mounting.
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Data from
"Naval Weapons of World War Two" by John Campbell
"Warships of World War II" by H.T. Lenton and J.J. Colledge
Special help from Dave Alton and Richard Worth
Page History

16 October 2005 - Benchmark
12 February 2012 - Updated to latest template
15 December 2013 - Added photographs of HMS Mackay