The 600-pounder 13.3inch RML Armstrong Gun ‘Big Will’
On 26 January 1863 the Illustrated London News reported on the new gun that Sir William Armstrong had delivered to Shoeburyness for trials.
Big Will at Shoeburyness
The article stated that:
This gun is of sufficient size to throw an elongated projectile averaging 600 lb., and is really a most ponderous affair, weighing 22½ tons, and resembles a telescope of corpulent dimensions. This appearance arises from the iron being so disposed as to be thickest at the breech, where the maximum strain has to be borne by the gun. As the shot leaves the bore, the gas generated by the ignition of the gunpowder exerts a gradually lessening strain, and the thickness of metal is, therefore, also gradually diminished by steps until, at the muzzle, it is comparatively thin.
The gun, in common with others that have been invented by Sir William, is ‘built up,’ as it is technically termed, and the following is the general principle of its manufacture:-
A bar of iron about 5 in. or 6 in. thick is heated to a red heat, and one end being fastened on a mandril or thick roller, which is set in motion by machinery, the bar is then wound in a spiral coil round the roller like so much ribbon. It is then knocked off and left to cool. The cylinder thus formed is again heated and welded into a compact hollow tube by powerful steam-hammers. The whole gun is made up by a series of these cylinders or tubes being joined endwise together, or one over the other as required. This is one of the principal merits of Sir William’s method of gun-making. Every one knows that a mass of twenty-two tons of iron could not be worked as one forging; but it can be built together in smaller portions ; and this ordnance is thus constructed. Several cylinders, being turned to a size. are joined together by welding so as to form a tube ; this is the bore of the gun, and it is terminated towards the breech by a large solid forging, bored out to the same diameter. This is called the breech-piece, and is made from solid forging, because it is the portion which is first acted on by the explosion of the charge. Over this long tube or bore thus formed, layers of thicknessing cylinders are put on hot, being by heat expanded so as to slip easily over the inner Cube, which is kept cool by a stream of cold water directed through it. These various layers of metal thicknessing, before they are subjected to this expansion by heat, have each to be turned up and bored out true, indeed, to the exactness of a hair’s breadth. When placed over the inner ring or cylinder and contracted by being cooled, they shrink around it with a force which no mechanical power can disturb: in this way strength is given where it is most needed to the gun. The 600-pounder has eight of these layers or cylinders, and is a triumph of mechanical skill. The breech is closed by a large iron plug, which is retained in its place by a second plug in rear of it-this latter being screwed in. This arrangement seems slightly defective; but there are, no doubt, sufficient reasons for adopting it. We believe that an improvement in closing the breech of built-up guns of this description has been carried out in the Royal Arsenal.
Big Will at Shoebuyness
The interior of this gun is rifled with ten grooves on the shunt principle, and the shot is made to rotate by means of ten rows of studs of gunmetal, which fit into these grooves. Each row contains five studs, and the studs, being of a softer metal than the bore, do no injury to it. The gun is 15 ft.6 inch in length, and the internal diameter of the bore is 13 3/10th inch. The external diameter at the muzzle is 1 ft. 9 in. It is 6ft 6inches from the extreme of one trunnion to the other. At ten degrees of elevatio, that is, with the muzzle raised so that the bore of the gun forms that angle with the level on which the platform is placed, this terrible piece of ordnance has thrown a shot over 4000 yards.
Reporting on the trial by the Ordnance Select Committee at Shoeburyness it was stated that:
Every alternate shot fired struck on the line aimed at, and even the greatest deviation was scarcely over four yards. The bursting charge of a shell, when exploded, instantaneously occupies a space of some thousands of cubic feet, so that four yards’ deviation is of little moment, and hardly diminishes the destructive effect of the shell. The shot and shell have to be lifted and the gun loaded by means of a small gyn, and the breech is elevated or depressed with the greatest ease by a small hydraulic lever. It is proposed to carry these guns in broadsides on iron-plated ships, but we anticipate great difficulties will arise in carrying out this intention.
In a gale of wind even 68-pounder guns sometimes break loose, and, as they weigh only 112 cwt., and the 600-pounder weighs 22½ tons, it could well be imagined what effect a heavy gale would have on the fastenings of the latter. Should it be found practicable to carry these heavy guns on board ship, no vessel yet afloat could last an hour against the fire of the 600-1b. steel shot. For fortresses and coast defences, where a solid foundation to carry the enormous weight can be. formed, and hydraulic power to move it can be brought into play, such weapons as this would be invaluable. If placed to command an important channel or tideway, where booms or similar obstructions could be placed to detain an enemy’s ships, even for half an hour, within range, their disablement or destruction would be certain.
The average weight of the shot is 600 lb. They are of three kinds: the first, solid, weighing 510 lb ; the second, hollow, to contain a bursting charge of gunpowder ; and the third (principally designed to be used against troops), a segment-shell, weighing 600 lb.
Big Will at Shoeburyness by Robert Taylor Pritchett
The 600-pounder, “Big Will “ as it is christened, was fired on the 11th inst., at Shoeburyness, and its powers tested against the floating target. This target was made of the best homogeneous iron, the outer plates being 4½ in. thick, firmly fixed on a backing of solid 18 in. thick, which was again backed by ¾in. iron plates and heavy T angle-iron, and supported in rear by props of thick fir. After an experimental shot at a wooden target with a 600-1b. shell, which smashed it to pieces. the iron target was moored at a range of 1020 yards. The first shell, 610 lb., with 25 lb. of powder as a bursting charge, missed the target, the gun having 2 deg. 10 min. of elevation. At 3 deg. 3 min. the second shell struck a little to the left of the bull’s-eye, and smashed through the entire frame, tearing out a piece 2 ft. by 1 ft. 8 in. in size, and literally shivering the backing to fragment, as shown in our Engraving on the preceding page. The whole of them ¾-inch iron backing was torn away, the plate in front above that struck had all its bolts broken, and the target was so disabled that it was not considered worth while firing at it at the 2000-yards range, as at first intended. The target was surrounded by a mass of iron fragments, and the experiment has successfully shown that no ship afloat could stand the terrific force of these 600-1b. shells. Sir William Armstrong and artillerymen may well congratulate themselves on the effect this gun has produced; and it is much to be doubted whether its shot will not penetrate any plates that can be used for men-of-war. On forts, any thickness of iron plating can be applied; but this seems to be a question not Considered at present by our authorities.
A subsequent article elaborated on the destruction of the target:
The sight presented by the target when struck was very grand. The shell, from its enormous size, was distinctly seen throughout its flight of 1000 yards from the gun to the target, and as the shell exploded an immense volume of smoke and flame instantly enveloped the target. Above the smoke pieces of plank were seen flying in the air, announcing the demolition of the box in the rear.
An engraving showed
...a section through the target as it would appear if cut vertically through the centre of the hole made by the shell: and it may not be out of place again to repeat that the target was composed externally of armour plating 4½ in. thick, resting upon and bolted to a solid backing of teak 18 in. thick, which backing was again supported by an inner plating and framework representing the body of the ship.
The shell appears to have exploded just as it entered the timber-backing, and it made a hole in the back of the target about four times as large as that in the front. The upper plate of the target, although not struck. was started by the force of the explosion fourteen inches forward from the face of the timber, drawing or breaking all its bolts. It would have fallen completely away, but for the obliquity of the target and the partial support it received from two or three of the broken bolts. The displacement of the armour plate and the damage to the timber backing is clearly shown.
Big Will was reported on favourably by the Ordnance Select Committee resulting in the War Office authorities ordering four more. Of these four that were built two were rendered unserviceable by experimental practice at Shoeburyness. A third was damaged but was effectively repaired and the fourth remained intact after proof. The cause of the failure in two guns was first: the steel tubes not having been tempered, secondly: they were fired on the shunt system, the defect due to sharp angles in this rifling being evinced by the fractures running along the angles in both guns.Thirdly: the guns having been fired with projectiles heavier than they were designed to carry, namely up to 670 pounds. The press carried a poem that was not very flattering entitled ‘Poor Big Will’.
In 1864 a further test was carried out, this time against Messers John Brown and Co.s thickest armour plate, no less than 11 inches thick, four feet long and by 3 and a half feet wide. It was held up vertically by two 12 inch beams of oak to which it was fastened by railway iron passing up its face on either side. Behind it was the Fairburn target of 5-inch plates and 1-inch inner skin with the same massive framework or iron rib beams. There was an interval of 12 inches between the plate and the Fairburn target. The proceeding commenced by firing two cast-iron round shot weighing 300lb levelled at 200 yards and ranged against a dummy plate alongside the target 11-inch plate to determine degree of elevation. Both were fired with 90lb of powder. Next Big Will was loaded with a 344lb shell. This struck the very centre of the target at a velocity of 1560 feet and in this one blow the experiments were finished. The target was gone! The oak beams were crushed to splinters and the plate itself smashed back against the Fairburn target and split into two pieces. The shell lay fourteen feet in front much flattened and cracked. The gun was uninjured.
The Hampshire Telegraph reported on 26 May 1866 that Big Will, the largest Armstrong gun was removed from the Portsmouth dockyard slung between two lighters to be landed near Southsea Castle and placed in one of the new batteries for trials.
Big Will at Southsea
In 1866 Captain H.D.P. Cunningham of the Gosport Volunteer Artillery was allowed to test his new traversing gear on Big Will. During a later demonstration Cunningham was able to traverse the 600 pounder 23ton gun at Southsea with one hand. His system was commended but not adopted as the chains presented an encumbrance to the gun crew.
In 1875 it was reported that Big Will still mounted and serviceable, but being experimental and retaining its shunt rifling it is not classed as a service gun and therefore does not appear in the Parliamentary return. The re-modelling of the Southsea batteries ended the life of Big Will. What happened to it is not known. It is shown in the 1869 armament returns but not in those of 1884.