The 6 Pounder Anti-Tank Gun
By 1938 tank armour thickness had increased significantly,
British Infantry tanks mounted 60mm of armour at the time and so there was
clearly a need for a more powerful gun than the 2 Pounder. Investigation into a
6 Pounder gun was initiated in 1938, initially the requirement was for anti-tank
guns but from the start the possibility of mounting the weapon in future AFVs
was allowed for. The General staff did not show interest in the project until
1939 when it was realised that tank armour was likely to progress past that of
which the 2 Pounder could deal with and so the intention was the ultimate
re-equipment of anti-tank regiments with a weapon superior to the 2 Pounder. In
January 1940 the Staff accepted the performance of a 6 Pounder (perforation of
70mm) with the proviso that if possible, the range should be something over 500
yards and in April the guns were approved for both tank and anti-tank mounting.
The Ordnance Board was also asked to provide solutions for 80,
90 and 100mm, the board recommended a 20lb shot of 3.45" calibre, the same
as the 25pdr but a piece more like the 3.7" AA gun, this requirement was
dropped in March 1940.
The 6 Pounder was designed primarily as an anti-tank gun but the
tank version only differed in having a lug on the breech ring and the first guns
produced were intended to be mounted on tanks. The designers of the A.20 tank
intention was to mount a gun heavier than the 2 Pounder, the 6 Pounder was
reported in January 1940 to be satisfactory if mounted with a special breech
ring, recuperator and with about 2 feet cut off the muzzle, it was intended to
mount the gun in the hull of the tank and this was criticised by the Ordinance
Board saying that it would be better to design a special gun and the performance
loss would make the 2 Pounder just as effective.
After Dunkirk the General Staff would have liked to have seen a
more powerful gun than the 6 Pounder but production considerations were
paramount, by the end of the year for manufacturing reasons as well as the ease
of tank mounting led to the design of a 6 Pounder with a shorter barrel that had
approximately the same ballistics. It was also clear that Germany, having
experience of 2 Pounders in France would increase their armour and had produced
50mm guns in quantity. At this point in the war Britain's production policy was
quantity and not quality and 6 Pounder production interfered with 2 Pounder
production, (estimated production rate was 2 6 Pounders for every 3 2 Pounders).
Gradually in 1941 there was a drive first for "6 Pounder
tanks at all costs" and then later for 6 Pounder anti-tank equipments, the
first tank guns (Mk III) were completed in June with full production commencing
at the end of October, the first anti-tank guns (Mk II) were completed in July.
Surprisingly unlike most other weapons, carriage production exceeded gun
production quite significantly in 1941 with full production commencing in June.
Most guns produced in 1941 were the tank version of the gun but it is important
to note that they could and were mounted on the anti-tank carriage.
The reduction in barrel length (43 calibre) reduced the muzzle
velocity of the gun, this was accepted on the grounds that the guns would
normally be in action at short ranges where the loss in performance would be
less marked. Action in North Africa in early 1941 had indicated the desirability
of increasing muzzle velocity, this was first done by the addition of a cast
muzzle break and an increase in propellant charge. Later it was decided to
revert back to the 50 calibre piece, these were introduced in August 1942.
6pdr Carriage Data
Carriage |
Mk I |
Weight with gun (Mk II) |
2,520lb |
Height (top of gunsheidl) |
50.5" |
Length |
185.25" |
Width |
71.5" |
Elevation |
15 degrees |
Depression |
5 degrees |
Transverse |
90 degrees, 45 right and 45 left |
Telescope |
No.22C |
6pdr Gun Data
Gun |
Mk II/III |
Mk III/V |
Weight with breech |
761lb |
727lb |
Weight without breech |
673lb |
640lb |
Total Length |
100.5" |
116.95" |
Barrel Length |
96.2" |
112.2" |
-
Mk I - Original Gun with L/50 barrel
-
Mk II - L/43 version for anti-tank Carriages
-
Mk III - L/43 version for tank mounting
-
Mk IV - L/50 version for anti-tank
-
Mk V - L/50 version for tank mounting
6 Pounder ammunition
Due to two different barrel lengths an thus different muzzle velocities
the 6pdr ammunition store is rather complicated. The first type of ammunition
was an Armour piercing shot, this was designed at end of 1939/start of 1940. The
AP ammunition was over time altered, muzzle velocity was increased with the
introduction of increased propellant "supercharge" and the weight of
the shot was also increased. Requirements for special penetrative performance
led to the request for APCBC in June 1942, the design for this shot was finalised
in January 1943 but beforehand a simpler design of APC had been approved in
October 1942. In July 1943 design of composite rigid ammunition was called for,
the design for this was approved in October 1943. Discarding Sabot
ammunition was called for in November 1943 and this was approved in January
1944.
6 Pounder Cartridges
Nature and Mark |
Charge |
Length |
Used with projectiles |
High Explosive Mk IT |
2.34lb |
24.5" |
HE Mk VIT |
High Explosive Mk IIT |
2.34lb |
24.42" |
HE Mk XT |
Armour Piercing shot IT |
1.84lb |
23.25" |
AP Shot I-IVT |
Armour Piercing shot IIT |
2.34lb |
23.25" |
AP Shot I-IVT |
Armour Piercing Shot IIIT |
1.84lb |
23.25" |
AP Shot V-VIIT |
Armour Piercing Shot IVT |
2.34lb |
23.25" |
AP Shot V-VIIT |
High Velocity Armour Piercing Shot IT |
2.44lb |
23.25 |
AP Shot I-IVT |
High Velocity Armour Piercing Shot IIT |
2.44lb |
25.25 |
AP Shot I-IVT |
Armour Piercing shot with cap IT |
1.84lb |
23.18" |
APC Shot VIIIT |
Armour Piercing shot with cap IIT |
2.34lb |
23.18" |
APC Shot VIIIT |
Armour Piercing Cap Ballistic Cap IT |
2.36lb |
26.27" |
APCBC Shot Mk XT, XVT |
Armour Piercing Discarding Sabot |
2.17lb |
|
APDS IBT |
6 Pounder Projectiles
Nature and Mark |
Length |
Dimension over body/ Driving
Band |
Weight |
AP Mk IT |
6.77" |
2.235"/2.31" |
6.28lb |
AP Mk IIT |
6.77" |
2.235"/2.31" |
6.28lb |
AP Mk IIIT |
6.77" |
2.235"/2.31" |
6.28lb |
AP Mk IVT |
6.84" |
2.235"/2.31" |
6.3lb |
AP Mk VT |
6.81" |
2.235"/2.31" |
6.28lb |
AP Mk VIT |
6.84" |
2.235"/2.31" |
6.3lb |
AP Mk VIIT |
6.81" |
2.235"/2.31" |
6.28lb |
AP Mk VIIIT |
6.81" |
2.235"/2.31" |
6.44lb |
HE VIT |
7.21" |
2.235"/2.31" |
6.28lb |
HE XT |
7.21" |
2.235"/2.205" |
6.54lb |
APC Mk VIIIT |
6.77" |
2.235"/2.31" |
6.34lb |
APCBC XT |
9.6" |
2.235"/2.31" |
7.13lb |
APCBC XVT |
9.6" |
2.235"/2.31" |
7.11lb |
APDS IBT |
|
|
3.31lb |
As you can there is a large number different projectiles and
cartridges so compiling a full list of penetration figures will probably not be
possible. Penetration figures vary from source to source and shot to shot
so the following table should only serve as a guide.
6 Pounder Penetration Table
Gun |
Shot type |
Muzzle Velocity |
Angle |
Armour |
500 yards |
1000 yards |
2000 yards |
Mk II/II |
AP |
2650fps |
30 |
MQ |
73 |
62 |
41 |
|
|
|
30 |
FH |
64 |
51 |
31 |
Mk II/III |
AP |
2800fps |
30 |
MQ |
79 |
66 |
44 |
|
|
|
30 |
FH |
69 |
55 |
34 |
Mk II/III |
APC |
2800fps |
30 |
MQ |
72 |
61 |
40 |
|
|
|
30 |
FH |
88 |
72 |
45 |
Mk II/III |
APCBC |
2630fps |
30 |
MQ |
68 |
60 |
44 |
|
|
|
30 |
FH |
80 |
73 |
57 |
Mk IV/V |
AP |
2900fps |
30 |
MQ |
82 |
71 |
48 |
Mk IV/V |
APC |
2900fps |
30 |
MQ |
78 |
67 |
44 |
|
|
|
30 |
FH |
93 |
76 |
48 |
Mk IV/V |
APCBC |
2780fps |
30 |
MQ |
86 |
80 |
68 |
|
|
|
30 |
FH |
97 |
82 |
64 |
Assumed IV/V |
APCR |
- |
30 |
MQ |
109 |
90 |
75 |
Assumed IV/V |
APDS |
4000fps |
0 |
MQ |
173 |
153 |
119 |
|
|
|
30 |
MQ |
138 |
123 |
95 |
6 Pounder gun and Carriage production by year (UK only)
|
1940 |
1941 |
1942 |
1943 |
1944 |
1945 |
6pdr Guns |
- |
201 |
17,854 |
16,586 |
1,964 |
- |
6pdr Carriages |
- |
419 |
4,666 |
6,945 |
405 |
- |
Airborne Carriage |
- |
- |
37 |
390 |
655 |
286 |
Carriage tops for SP |
- |
- |
166 |
19 |
- |
- |
6 Pounder ammunition production by year (Filled only), o = overseas imports.
|
1940 |
1941 |
1942 |
1943 |
1944 |
1945 |
AP |
- |
160,000 |
6,150,00 |
7,130,000 |
- |
- |
AP(o) |
- |
- |
1,838,000 |
1,330,000 |
30,000 |
|
APC |
- |
- |
- |
534,000 |
- |
- |
APCBC |
- |
- |
- |
1,125,000 |
1,143,000 |
- |
APCBC(o) |
- |
- |
- |
430,000 |
2,044,000 |
|
APDS |
- |
- |
- |
- |
217,000 |
158,000 |
HE |
- |
NF |
396,000 |
1,865,000 |
286,000 |
172,000 |
Sources - 6pdr Handbook, Cromwell Handbook, AVIA 46 187, WO 185/178, DEFE 15 180