AMTB
Anti Motor Torpedo Boat.

AP
Armour Piercing. A shell with a thick casing designed to penetrate the armour of a ship and explode internally. The Fuze was in the base of the shell so that it was not crushed in the passage of the shell through armour. Some other types of shell such as Common Pointed had a base fuze.

A Ballistic Cap was fitted to the nose of the shell. This was lightweight and streamlined to assist passage through the air. On impact, the shell would simply pass through the Cap and on to the armour beyond.

BL
Breech Loading. The shell and propellant charge, normally in cartridge or bagged form, are inserted from the breech (rear) end of the gun. This meant that longer barrels with greater accuracy could be used.

Cartridge
The charge which propels the shell from the gun. It was in a bag, usually silk, and came in various weights depending on the gun and range required. The charge in the early days was Prismatic Powder, later Cordite. Prismatic Powder was not really a powder, but shaped into hexagonal or octagonal pieces. giving better burning characteristics, and was safer than gunpowder, producing less smoke.

Cordite was a smokeless propellant made from nitroglycerine and nitrocellulose. It was extruded in to long strips, rather like a cord. The strips were bundled together to make propellant charges.

Cartridge, or Round also applies to small arms (pistols & rifles) ammunition and refers to the propellant charge, primer, percussion cap and projectile all being in one unit. The word ‘bullet’ is often erroneously used to describe a cartridge. Some artillery shells were in this form as well; 3-Pounder, 6-Pounder and 18-Pounder for example.

CASL
Coast Artillery Searchlight.

DEL
Defence Electric Light (searchlight).

DRF
Depression Range Finder. An optical instrument used to obtain the range of a target. These were installed at a great a height as was possible. The angle of depression which set the sights on the target's waterline was used to calculate the range by means of trigonometry.

Fuze
A small device which initiates the detonation of a shell or munition. Fuzes may be instantaneous, have a delay mechanism, or may be set to initiate in the proximity of a target.

HE
High Explosive. The Shell has a powerful explosive filling and the fuze was in the nose of the shell. It was designed to explode on impact and scatter lethal shards of metal.

Magazine
A place to store shells and cartridges. Usually underground with shells and cartridges being kept is separate thick walled rooms.

ML
Muzzle Loading. Early cannon had their propellant charge and cannon ball or shell loaded from the muzzle. The bore of these guns was smooth.

PF Cell
Position Finding Cell. Instrumentation in these took bearings on the target. The bearings were used in conjunction with other Cells and a Range Finder to accurately plot the position and course of a target vessel.

QF
Quick Firing. The Shell and propellant cartridge were usually all in one unit, a brass case containing the propellant charge, firing cap and primer with the shell on the open end. The whole unit was called a Round of Ammunition. This gives a very fast rate of fire. The smaller guns in Singapore used this type of ammunition.

The 6-Inch QF used ‘Separate QF’. The appropriate weight of bagged propellant charge was in the brass case with the shell separate. One man would insert the shell, a second the brass case containing the propellant. The breech was closed and the gun fired. There was no need for priming charges. Separate QF was required as the combined weight of the 6-Inch Shell, propellant charge and brass case would be difficult to handle.

R.A.O.C.
Royal Army Ordnance Corps.
An Ancestor of the Royal Logistic Corps. Responsible for stores and ordnance among other things. Although not usually in to construction, they were responsible for building the Buona Vista Battery.

R.A.S.C.
Royal Army Service Corps, another ancestor of the Royal Logistic Corps. Responsible for a range of activities especially transport and the aerial delivery of supplies.

R.E.
The Royal Regiment of Engineers. Gun emplacement construction and bridge building were two of the responsibilities of the Engineers.

RML
Rifled Muzzle Loading. A set of grooves are cut in to the inside face of the barrel. Studs on the shell fitted into the grooves and imparted a spin to the shell when fired. This greatly increased accuracy.

Trunnion Level
This is the height of the swivel point of a gun above mean sea level. The term goes back to the days when gun barrels were fitted with trunnions, two small arms sticking out of the sides of the barrel on which the barrel swivelled in a vertical direction.