6 pounder Gun

Once the 2 pounder Anti-Tank Gun had been issued, work started on its replacement. A 6 pounder 57mm calibre weapon was chosen because the calibre had been in use since the 1880’s therefore barrel making machinery & ammunition production were available along with a knowledge of the ballistics. The design was ready in 1938 & a test gun made & fired in 1939. The design was then sealed & put aside until it was needed.

The gun should have been put in to production in 1940 but the heavy losses of 2 pounder guns needed immediate replacement. To put the gun into production & train the crews would have taken considerable time so it was decided to continue production of the 2 pounder for the time being. The first 6 pounders were not made until November 1941. By May 1942, 1,500 guns a month were being produced.

The guns replaced the 2 pounders in anti-tank regiments & later were issued to infantry battalions as stocks allowed. Some were given to the Soviet & American armies. The latter copied it as the 57mm Gun. The gun originally had a traverse handwheel but this was changed on production models to free traverse controlled by the layer having a shoulder pad under his arm & pushing the gun from side to side. This system had been used for many years in coast & light naval guns.

The 6 pounder was also the principal British tank gun for a lot of the war. An auto-loader was produced for a proposed 1 man tank destroyer, superseded by the issue of the 17 pounder but the Royal Navy took the project over as armament for fast coastal craft. It was very successful.

The RAF also showed an interest, mounting the 6 pounder in a Mosquito as an anti-submarine weapon. 12 guns were fitted operating over the Atlantic with some success. They were replaced by rocket systems.

Gun

Mark 1Original development model. A few made in 1939, none issued to service
Mark 2Production model for towed carriage
Mark 3For tanks. As Mk 2 but with lugs on the breech ring for tank mounting
Mark 4As Mk 2 but barrel 16 inches longer with a muzzle brake to improve muzzle velocity
Mark 5As Mk 3 but 16 inches longer with muzzle counterweight
‘C’ Marks 3, 4, 5 As Mk’s 3, 4, 5 but Canadian manufacture

Carriage

Mark 1Original split trail production model
Mark 1AAs Mk 1 but different axle-tree & wheels
C Mark 1Mk 1 Canadian manufactured
Mark 2Slightly simplified design as a production alternative to Mk 1. Not adopted
Mark 3Lightened Mk 1 for airborne use

Data

Gun Mk 2 on Carriage Mk 1

Weight of gun & breech mechanism768 lbs
Total Length100.95 inches
Length of Bore96.2 inches (43 calibres)
Rifling24 grooves, uniform Right Hand 1/30
Breech MechanismVertical sliding block, semi-automatic, percussion fired
Elevation-5° to +15°
Traverse45° Left & Right
Recoil SystemHydro-spring, constant, 30 inches
Weight in action2,521 lbs
Mk 4 Gun as above except
Length of Gun116.95 inches
Length of Bore112.2 inches (50 calibres)

Performance

Firing standard 6 lb AP Shot

Muzzle Velocity2,693 feet/second
Maximum Range5,500 yards
Penetration74 mm at 1,000 yards, 30° angle

Firing Shot, APDS Mk 1T

Weight3.25 lbs
Muzzle Velocity4,050 feet/second
Penetration146 mm plate at 1,000 yards

Ammunition

Shot, Armour Piercing Marks 1 to 7TPlain steel solid shot
Shot, Armour Piercing Cap Mark 8TSimilar to AP shot plus penetrative cap to attack face hardened plate
Shot, Armour Piercing Cap Ballistic Cap Mark 9TAs for APC but with a light ballistic cap. Improved penetration
Shot, Armour Piercing Composite Rigid Mark 1TProvided in small quantities October 1943. A tungsten core built up to full calibre by a light alloy body. Performance good at short range but dropped of rapidly as range increased.
Shot, Armour Piercing Discarding Sabot Mark 1TIssued June 1944. Tungsten core in light steel sheath. Built up to full calibre by 4 piece light alloy sabot discarded at the muzzle on firing
Shell, High Explosive Mark 10TNose fuzed HE shell fitted with percussion fuze No. 243