During World War II, many of these guns were used on minor warships and some of the older destroyers. Some were also employed in coastal batteries.
The Mark I and Mark III had similar ballistic performance, but differed in construction. The Mark I had an A tube with short chamber liner, half length wire, full length jacket and a screw breech ring connected the jacket to the breech bush over the A tube. Mark IA differed in that the A tube was thicker over the front of the chamber. The Mark III had an A tube, wire of reduced length, B tube and jacket with a screwed C hoop connecting them. Ten Mark I, eight Mark IA and 261 Mark III guns were manufactured. There were also seven Mark I/III built like the Mark III but with the breech ring and bush as the Mark I. Five of these were later converted entirely to the Mark III design and then designated as the Mark III*.
The Mark II was a trunnioned gun of the same performance as the Mark I. Eight guns were made to rearm the old battleship Temeraire and the paddle steamer Sphinx.
|Designation||4"/40 (10.2 cm) QF Marks I, II and III|
|Ship Class Used On||Invincible class, Amethyst and Pelorus light cruiser classes, various sloops and gunboats|
|Date Of Design||About 1904|
|Date In Service||1908|
|Gun Weight||2,952 lbs. (1,339 kg)|
|Gun Length oa||165.3 in (4.199 m)|
|Bore Length||160 in (4.064 m)|
|Rifling Length||143.5 in (3.645 m)|
|Chamber Volume||213 in3 (3.49 dm3)|
|Rate Of Fire||about 8 - 10 rounds per minute|
|Projectile Types and Weights||HE - 25 lbs. (11.3 kg)
HE - 31 lbs. (14.1 kg)
(see Note 1)
|3.56 lbs. (1.6 kg) Cord 15
5.11 lbs. (2.3 kg) MD16
|Muzzle Velocity||Small HE - 2,370 fps (722 mps)
Large HE - 2,300 fps (701 mps)
|Approximate Barrel Life||N/A|
|Ammunition stowage per gun
(see Note 2)
|Invincible: 100 rounds
1)This may have been the only gun for which Cordite MD was made in a tubular form as well as in cords.
2) Original outfit for Inflexible was 50 CP and 50 HE, later changed to 30 CP and 70 HE.
|Elevation||With 25 lbs. (11.3 kg) or 31 lbs. (14.1 kg) HE Shell|
|WWI Range @ 20 degrees||9,600 yards (8,780 m)|
Amethyst (12) and Pelorus (8): PI
Invincible (16): PI*
|Elevation||PI: -10 / +20 degrees|
|Elevation Rate||Manually operated, only|
|Train Rate||Manually operated, only|
|Note: Invincible was sunk with these guns but Indomitable was rearmed with the 4"/45 (10.2 cm) Mark VII in April 1917and Inflexible was rearmed with the 4"/45 (10.2 cm) Mark IX in July 1917.|
25 February 2007 - Benchmark
10 January 2009 - Added remark concerning tubular cordite
12 February 2012 - Updated to latest template and added mounting information
03 February 2014 - Added ammunition stowage information, photograph of Inflexible and note about rearming of Indomitable and Inflexible