7 Inch RML Gun
The gun is mounted on a Garrison Carriage. This swivelled on a spigot fixed in the emplacement floor, and there are two wheels sitting on metal rails, at each end of the Carriage to support it and to allow traversing. The Carriage sloped upwards towards the rear, and when the gun fired, it recoiled up the slope and was retained at the rear of the carriage. The barrel was then depressed to enable the gun-crew to reload it without exposing themselves over the top of the emplacement. Once reloaded the gun would be run back to the front of the carriage and the barrel elevated to the correct firing angle.
A charge of 20lbs of gunpowder gave the gun a range of 5,500 yards. The shells were shaped and has brass studs set in to the body. These studs engaged in the rifling of the barrel and imparted a stabilising spin to the shell when the gun was fired. This increased accuracy and ensured that the pointed end struck the target first. This allowed contact fusing to be used. A crew of ten men served the gun. They transversed the gun with a block and tackle and levers which were called handspikes. The gun was elevated by a gear mechanism.
Shells can be seen to the left of the gun, and gun powder cartridges in protective cases are against the right hand side of the emplacement. Also seen are some handspikes on the right and a rammer on the left. This was used to ensure that the propellant charge and shell were pushed all the way down the barrel. A friction primer fired the gun. A gunner tugged on a lanyard which operated the primer.
The 7 Inch RML Gun was developed from a naval gun, as indeed were other types of gun used as coastal artillery.