The Twin 6 Pounder QF (Quick Firing) Gun had its origins in the 1920s. The Royal Artillery Committee was tasked with investigating the possible development of a new QF Gun for defence against torpedo boats. These were small fast craft, ideal for raiding harbours, so an effective quick firing gun capable of laying down heavy fire against them was necessary.
The Westwood Works of Peterborough, England, submitted a design for such a gun in 1925. This consisted of two 6 Pounder QF Guns with Semi-automatic Breeches housed in a three sided metal shield with a roof. The whole assembly was mounted on a Cradle attached to a pivoting Pedestal Mounting.
Trials of the gun commenced in 1928, and the gun was eventually accepted for service in 1934. It was 1937 before the first production gun, the ‘Q.F. 6-PR. 10 Cwt Mark 1’ on a Mark 1 Mounting, entered service. This gun was mounted at an AMTB Battery in Singapore.
Pre-WWII, the Twin 6 Pounder armed the Changi Outer (Palm), Pulau Sejahat, and the Berhala Reping AMTB Batteries. Post War, they armed OSO at Fort Siloso, Batu Berlayar, and Berhala Reping.
The guns were constructed from steel, and weighed 9 cwt 1 qr 24 lb (480 kg). The barrel was rifled with 24 grooves. The gun body was fixed to a platform and mounted on a Mark I Mounting, capable of all-round traverse. The complete gun assembly and mounting was bolted to a Holdfast in the emplacement floor. The Holdfast consisted of ten bolts buried vertically in the concrete floor. Each bolt being 34·8 inches (88·4 cm) in length.
Two Ammunition Trays were attached to the platform, one each side of the gun body. The platforms were pivoted so that ammunition was always at the correct angle for the loading team. Each tray could carry 36 rounds of ammunition, stacked pyramid fashion. Because the gun could fire so quickly, additional ammunition would be held on Ammunition Trolleys, each carrying 36 rounds. These trolleys were on a curving track running around the top of the emplacement.
The gun mounted at Siloso after the war had been modified in the light of experience. It was modified so that as well as engaging sea targets, it could also be used in an anti-aircraft role.
Ammunition was Fixed QF. It comprised a primer and a propellant charge in a brass case to which was attached the projectile (shell) and fuse. The complete unit being called a ‘Cartridge’ or ‘Round’.
The shell was filled with H.E. and was made from forged steel. It weighed 6 lb 4 oz 48 dr (2·85 kg). The shells could be fitted with a tracer element if required. This would enable the flight of the shell to be followed visually.
A full charge of 1lb 6oz 3 dr (0·63 kg) of cordite propellant gave the gun a range of 5150 yards (4709 metres) at an elevation of 7·5°. A reduced charge of 13 oz 4 dr (0´375 kg) was also available. This gave a range of 3,900 yards (3566 m).
The gun was capable of a rapid traverse, and despite being hand-loaded, the gun could achieve a rate of fire in excess of of 72 rounds a minute when served by a well drilled gun crew. The guns shields were fitted with a powerful extractor fan on the roof, to remove the build up fumes which would otherwise affect the gun crew.