Originally designed in 1893, the 12 Pounder QF Gun was manufactured at the Elswick Ordnance Company, Newcastle upon Tyne. The version mounted at Fort Siloso in 1898 and 1941 was the 12 Pounder of 12 Cwt. The early guns did not have an extractor for spent cases, which had to be removed with a special extraction tool.
12 Pounders saw service at; Batu Berlayar, OSO (Fort Siloso), Berhala Reping and Ladang.
The gun was made from steel and mounted on a pedestal bolted to a holdfast in the emplacement floor. The gun weighed 12 cwt (610 kg), and had a bore of 3 inches (7.62 cm). The barrel was rifled. The gun was breech loaded, the breech being opened and closed quickly by a cam lever. It could be fired either by percussion or electrically. An automatic sight was fitted above and to the left of the barrel. The gun could be depressed 15° and elevated 20°. The gun could traverse a full 360°.
The gun fired QF Fixed Ammunition. That is, the projectile (shell) was attached to the cartridge case containing the propellant charge and the primer. The propellant charge was made up of 1 lb 15 oz (0.88 kg) of size 15 cordite in a brass case. If size 10 cordite was used, the charge would have been 1 lb 9½ oz (0.71 kg).
The projectile (shell) contained high explosive, and weighed 12.5 lb (5.67 kg) filled with fuze fitted.
At a range of 1000 yards (914 m), the projectile could penetrate 4 inches (10.2 cm) of steel.
The detachment is composed of seven men. The service of the gun is divided between them as follows:-
A well drilled detachment could get away up to 20 rounds per minute.