To allow for expansion of the walls of the case when being ejected after compression, the dies are turned slightly smaller (say 3/1000 parts of an inch) than the required finished size.
After being pressed, the primer holes of the cartridge case (known as the plain and platform holes respectively) are rectified by a double-reamer, the case revolving in a sleeve bored to correct taper of the outside diameter of the case, this assuring concentricity of the two holes, and ensuring that the primer face and percussion cap lie flush with the base of the case. A forming tool, having a non-cutting face which acts as a depth guide against the base, corrects the outer rim and shoulder.
A hand-tapping machine clamped centrally to a suitable fixture on a bench was devised for re-tapping primer-holes. This consists of a floating bracket which accurately guides the tap into the existing thread, at the end of the tap being fixed a hand-operated capstan wheel, and on the tap a stop to regulate the depth of the screw.
A similar apparatus fitted with a sliding screw-driver removes the primers; the cartridge case in either event being securely held and easily fixed or released in a central clamp.
Finally, after being immersed for a couple of minutes in a solution of sulphuric acid, the cartridge case is polished with sand and sawdust on a wooden pad covered with tapestry and revolving in a lathe at 300 or 400 revolutions per minute.
The result of garnering in and renovating these cartridge cases instead of turning them adrift in the battle area, reckoned in figures of pounds, shillings, and pence, was undoubtedly very considerable; for apart altogether from the saving effected in the cost of labour when repairing old cartridge cases as compared with the manufacture of new ones, the weight of metal alone contained in a couple of million cases may be taken at approximately 1500 tons; and with yellow metal costing £82 12s. 0d. per ton, the saving in metal alone amounts to no less than £123,900.
[CHAPTER VI]
GUNNERY AND PROJECTILES
(Rudimentary Notes and Notions)
"The Prussian was born a brute, and civilisation will make him ferocious."
Goethe.