The Mark VI was an Elswick gun of Pattern "S" originally built for six Chilean destroyers of the Almirante Lynch class, but four of these destroyers were taken over by the British at the start of World War I. Post-war, the three surviving destroyers were given back to Chile.
The Mark X was a single Elswick gun of Pattern "Q" similar in design and performance to the Mark VI. The Mark X was probably never used afloat.
Mark VI constructed of A tube, breech piece and B tube, wire over the breech piece, full length jacket, breech ring and breech bush screwed into the breech piece. Used a screw breech block whose design was similar to that for the QF Mark III. A total of 29 Mark VI guns were manufactured.
| Designation | 4"/40 (10.2 cm) QF Mark VI |
|---|---|
| Ship Class Used On | Britain: Faulknor class, Swordfish and Mimosa
Chile: Almirante Lynch class (ex-Faulknor class) |
| Date Of Design | N/A |
| Date In Service | about 1914 |
| Gun Weight | 1.297 tons (1.41 mt) |
| Gun Length oa | 165.1 in (4.194 m) |
| Bore Length | about 160 in (4.064 m) |
| Rifling Length | N/A |
| Grooves | N/A |
| Lands | N/A |
| Twist | N/A |
| Chamber Volume | 240 in3 (3.933 dm3) |
| Rate Of Fire | about 15 rounds per minute |
| Type | Separate |
|---|---|
| Projectile Types and Weights | HE: 31 lbs. (14.06 kg) |
| Bursting Charge | N/A |
| Projectile Length | N/A |
| Propellant Charge | 5.0 lbs. (2.27 kg) MD16 |
| Muzzle Velocity | 2,300 fps (701 mps) |
| Working Pressure | N/A |
| Approximate Barrel Life | N/A |
| Ammunition stowage per gun | N/A |
| Elevation | Distance |
|---|---|
| 25 degrees | 11,630 yards (10,630 m) |
| Designation | Single Mounting
Faulknor (6) 1, Mimosa (1 or 2) and Swordfish (N/A): PXI |
|---|---|
| Weight | N/A |
| Elevation | -5 (?) / +25 degrees |
| Elevation Rate | Manually operated, only |
| Train | 360 degrees |
| Train Rate | Manually operated, only |
| Gun recoil | N/A |
- ^Survivors of the Faulknor class were rearmed with two 4.7"/45 (12 cm) BL Mark I guns and two 4"/40 QF Mark IV guns during World War I.
"Naval Weapons of World War Two" and "British Naval Guns 1880-1945 No 18" article in "Warship Volume X" both by John Campbell
25 March 2008 - Benchmark
12 February 2012 - Updated to latest template
11 December 2021 - Converted to HTML 5, added photograph of HMS Botha