Ordnance QF 32-pounder

Ordnance QF 32-pounder
The 32-pdr mounted in the Assault Tank A39 Tortoise
Type	Gun
Place of origin	United Kingdom
Service history
Used by	UK
Wars	World War II
Specifications
Mass	2,972 kg (6,552 lb)
Shell	94×909mmR[1]
Calibre	94 mm (3.7 inches)
Barrels	5.89 m (L=62.6)
Muzzle velocity	5,050 ft/s (1,540 m/s) maximum (APDS)
Effective firing range	1,350 yd (1,230 m)
Maximum firing range	5,000 yd (4,600 m)

The Ordnance QF 32 pounder or (32-pdr) was a British 94 mm gun, initially developed as a replacement for the Ordnance QF 17-pdr anti-tank gun.

The only use of the 32-pounder was as the armament for the pilot vehicles of the Tortoise heavy assault tank.

Development

Development started in October 1942, due to a General Staff order for a successor to the 17-pdr gun.^[2] Basic requirements involved the new gun to be "at least 25% more effective" than the 17-pdr. Initial focus was on development of a 55-pdr gun, although advancements in 17-pdr ammunition meant the advantages that would be secured by the 55-pdr were no longer as desirable, while the 55-pdr would suffer from considerable disadvantages such as the difficulties in the handling and stowage of ammunition. Other options considered included a 76 mm (3-inch) 17-pdr firing a 4 lb (1.8 kg) Armour Piercing Composite Rigid (APCR) shot at a muzzle velocity of 3,550 ft/s (1,080 m/s)^[2] a 3-inch tapered to 2.25-inch (76 to 57 mm) "squeeze bore" firing a 3.5 lb (1.6 kg) Armour-Piercing, Composite Non-Rigid (APCNR) shot at 4,500 ft/s (1,400 m/s) and a 3.45 in (88 mm) calibre.^[2] Eventually, a 3.7-inch 30-pdr gun was proposed for a standard calibre, as it had a better margin for improvement.^[3] The QF 3.7-inch anti-aircraft gun was selected as the basis for the 30-pdr anti-tank gun in September 1943 and for pilots to be built.

During development, it was proposed that a 37 lb (17 kg) shot would give better performance, and this new design was trialled as the QF 37 pdr EX1 in June 1944. Following firing trials, the 37 lb shot was dropped for a 32 lb (15 kg) shot, and the gun was accepted as the QF 32-pdr.

At least one 32-pdr was developed as an anti-tank gun on a wheeled carriage and a single example using a novel form of muzzle brake was installed in a de Havilland Mosquito FB Mk. XVIII as an up-gunned version of the 'Tsetse', in place of the 57 mm 6-pounder Molins gun. While flight trials did not take place until after the war had ended, the aircraft flew and the gun fired without problems.^[4]

The 32-pdr fired a 32 lb (14.5 kg) armour-piercing shot at a muzzle velocity of 3,050 ft/s (930 m/s) and a 15.3 lb (6.9 kg) Armour-piercing discarding sabot (APDS) shot at 5,050 ft/s (1,540 m/s).

During firing trials on 28 June 1945, the 32-pdr Shot Mk.3 APDS shot penetrated 200 mm (7.9 in) of rolled homogeneous armour at 50° – a line of sight equivalent of 311 mm (12.2 in) - and 4,880 ft/s (1,487 m/s) on impact, which meant that its penetration surpassed those of the 17-pdr and 20-pdr APDS rounds, and could even rival early armour-piercing fin-stabilized discarding sabot (APFSDS) rounds in raw penetration. The 32-pdr gun could have easily penetrated the front hull of the Tiger II (Konigstiger) and Jagdtiger; it would have been the only allied anti-tank gun that could do so in the Second World War. By comparison the M308 HVAP shell of the 90 mm M3 anti-tank gun on the US M36 Gun Motor Carriage could penetrate 114 mm (4.5 in) at 50° at 100 yd (91 m).^{[citation needed]}

Development was halted with the end of the war: the 17-pdr was replaced by the 20-pdr for tank use, and by the 120 mm 'Battalion Anti Tank' recoilless rifle as an anti-tank artillery weapon. For infantry use it was intended to replace the 17-pdr with anti-tank guided missiles.

Ammunition

The ammunition was separate projectile and propelling charge. A number of projectiles were developed or planned including:

• H.E. Mk 1
• H.E. Mk 2
• H.E. Mk 3
• APCBC/T Mk1
• APCBC/T Mk2
• APCBC/T Mk3

The "T" indicated the shot had a tracer element to allow tracking it in flight.

Specification

• Calibre: 94 mm (3.7 in)
• Barrel length: 62.6 calibres, 5.89 m (19 ft 4 in)
• Chamber pressure 49,200 psi (339 MPa)
• Weight: 2,972 kg (6,552 lb)
• Maximum effective range: 4,600 m (5,000 yd)
• Cartridge: 94×909mmR

See also

• British standard ordnance weights and measurements

References

• Allied Secret Weapons a Purnell's History of the World Wars Special. Phoebus, 1975, (No ISBN)
• https://search.worldcat.org/ja/title/1295166006

This page was last edited on 14 January 2024, at 17:47