Following the war, four guns were sent to the Caspian in 1919. During World War II, many guns were used to arm DAMS merchantmen.
The Mark XI was the Mark VIII adapted for submarine use.
The Mark VIII was constructed of A tube, breech piece, B tube to the muzzle, wire over the breech piece, jacket, breech ring and bush screwed into the breech piece. Used a Welin block with a "pure couple" breech mechanism. Later guns and the Mark XI had a tapered inner A and A tube instead of the A tube, B tube and Breech piece. Firing could be via either percussion or electrical means. Actual bore length of all guns was 39.8 calibers. When worn, the guns were repaired by boring out a part of the A tube and inserting a tapered liner.
A total of 246 of the Mark VIII guns were produced, of which 194 still remained in 1939. Thirty Mark XI guns were manufactured, all of which were apparently scrapped by 1939.
|Designation||4"/40 (10.2 cm) BL Mark VIII
4"/40 (10.2 cm) BL Mark XI
|Ship Class Used On
(see Note 1)
Destroyers: Swift, later Tribals starting with Saracen, first 13 members of the K class, Acasta class members Acasta, Midge and Spitfire
Submarines: E2, E11, E12, E14, E21 and E25
"Fly" class river gunboats
Some P ships and Q ships
Australian Swan class
|Date Of Design||About 1904|
|Date In Service||1908|
|Gun Weight||1.296 tons (1,317 kg)|
|Gun Length oa||166.4 in (4.227 m)|
|Bore Length||159.2 in (4.044 m)|
|Twist||Uniform RH 1 in 30|
|Chamber Volume||298 in3 (4.88 dm3)|
|Rate Of Fire||About 6 - 8 rounds per minute|
1) The Japanese destroyer Sakaki carried one of these guns in 1918. This was probably installed when she was rebuilt after being torpedoed by the Austrian submarine U.27 in 1917.
2) Modified HA guns were used on the K class destroyers, Acasta, Midge and Spitfire (one gun).
|Projectile Types and Weights||HE - 31 lbs. (14.06 kg)
CPC - 31 lbs. (14.06 kg)
Shrapnel - 31 lbs. (14.06 kg)
|Propellant Charge||World War I: 5.38 lbs. (2.4 kg)
World War II: 5.5 lbs. (2.5 kg) SC103
|Muzzle Velocity||2,287 fps (697 mps)|
|Approximate Barrel Life||N/A|
|Ammunition stowage per gun||N/A|
|Note: Projectiles were 3crh.|
|Elevation||With 31 lbs. (14.1 kg) HE Shell|
|Range @ 20 degrees||10,210 yards (9,340 m)|
Mark VIII (LA)
Swift (4), Tribals (2) and K (3): CPIII, CPIII*, CPV and CPVII
Mark VIII (HA)
K (3), Acasta (3), Midge (3) and Spitfire (1): N/A
|Elevation||All except HA conversions: -10 /
HA conversions: N/A, but probably about -10 / +70 degrees
|Elevation Rate||Manually operated, only|
|Train||CP type: 360 degrees
SI: About -120 / +120 degrees
|Train Rate||Manually operated, only|
|Note: HA mountings had a "trap door" gun pit which allowed higher elevations by letting the breech go below the mounting deck level. These guns were carried on a few K class destroyers and on the Acasta class destroyers Acasta, Midge and Spitfire (one gun).|
16 October 2008 - Benchmark
30 January 2009 - Updated HMS Swift picture caption to include link, added information in the Mount / Turret "Designation" section
29 February 2012 - Added mounting information
16 June 2012 - Added picture of HMAS Warrego