The First Epoch Early 14th Century to 1845

In the middle of the 18th cen tury progress was made in ord nance by boring from a solid casting instead of relying on hollow casting; this resulted in greater uniformity of bore. Also a more scientific attitude to bal listics (q.v.) was adopted. This attitude was mainly due to Benjamin Robins, inventor of the ballistic pendulum, who in 1742 published an important work, The New Principles of Gunnery. A result of his research and experiments was the introduction in 1779 of carronades. These were light short weapons of various calibres from 6 to 68 pounders in which windage was greatly reduced. A contrast between this weapon on its ship's mounting and a gun of the same calibre on a truck carriage is shown in figs. 4 and 5. More attention was also paid to the shape and weight of guns in relation to the stresses to be borne and less to external ornament. Trunnions were placed near the axis of the gun instead of below it, thus lessening the stresses on the carriage.

Hollow shot filled with explosive or incendiary mixtures were used from mortars in the middle of the i6th century, but ex plosive shell did not come into general use for guns until early in the 19th century. Their advent sounded the death knell of the wooden warship and soon became an incentive to the develop ment of steel through the impetus given to the production of protective armour. The 65 cwt. 8 in. shell gun was introduced into the British Navy after 1838 and took the place of the 32 pounder as the lower deck armament in line of battle ships and the main deck armament of frigates. The gun was 9 ft. long and fired a 56 lb. shell. It formed the principal armament of H.M.S. "Marlborough" as late as 186o.

This may be described as the "evolutionary era." It is notable for the great advance made in a short period through the intro duction of rifling for cannon and of a "built-up" construction in volving shrinkage, resulting in medium velocity weapons firing elongated projectiles of considerable penetrative power. This epoch embraced the Russian, American Civil and Franco-Prussian Wars. These contributed to the remarkable developments in ord nance, revived the armament firms of Europe that had gone into obscurity since the Napoleonic Wars, particularly Krupp (Ger many) and Schneider (France), and brought others into being, notably Armstrong Whitworth (Britain). The progress in me chanics and engineering of this industrial era, which included the introduction of the Bessemer and Siemens open-hearth method of making steel, was reflected in the advance in gun mechanisms, in recoil appliances and in the application of power to the working of guns. The inventive genius of the time was particularly exem

plified by the production of machine guns and automatic guns.

Introduction of Rifling.

The introduction of rifling owes much to Benjamin Robins who, in 1747, wrote: "Whatever state shall thoroughly comprehend the nature and advantage of rifled barrel pieces and . . . shall introduce into their armies their general use . . . will by this means acquire a superiority which will almost equal any thing that has been done at any time by the particular excellence of any one kind of arms." Rifling, by imparting a spin to the projectile as it travels along the spiral grooves in the bore, permits of the use of an elongated projectile and ensures its flight point first, which greatly increases accuracy. The longer projectile being heavier than round shot has a greater striking energy for the same muzzle velocity. The shape of the head can be designed to reduce air resistance, thereby increasing range. Though Robins was probably the first to give reasons based on sound principles why rifling was desirable, the fact that it was helpful in external ballistics had been appreciated since the early i6th century and a barrel exists at Woolwich, dated 1542, which is rifled with six fine spiral grooves. Straight groov ing was applied to firearms (muskets) as early as 1480 and this practice of grooving the bore of a musket without any twist was extensively used during the 16th century. Probably rifling evolved from the early observation of the action of the feathers on an arrow and from the practical experience of cutting channels in a musket, originally to reduce fouling, being found beneficial to the weapon's accuracy. Towards the end of the 18th century the importance of rifled small arms and their necessity had been appreciated. The War of Independence contributed to this re sult ; the Americans early realised the value of the rifled musket. Elongated bullets, however, did not begin to replace spherical until 1828. It was not until a hundred years after Robins' experiments that any attempt to rifle guns was successful. In 1846 a Sardinian officer, Major Cavalli, and a Swedish officer, Baron Wahrendorff, both independently produced breech-loading rifled iron guns. The Cavalli gun had two grooves cut separately along the bore on opposite diameters, in which two projections, deep, on the 69 lb. cylindro-conical projectile, engaged. Promising results were obtained with both guns, though they were of a somewhat weak construction.