ORDNANCE. (See also ARMOR ; GUN, PNEUMATIC ; AND PROJECTILES.) PROGRESS ABROAD.—In June, 1879. a committee of ordnance was appointed in England for a full consideration of the relative advantages and disadvantages of muzzle loading and breech loading. The result was to commit the government to an experimental course of con struction of breech-loading guns of some of the heaviest calibers then in existence. The committee was dissolved in 1881, after having fairly launched the country into gun-making upon the following principles : (1) A heavy steel tube, reinforced over the rear portion with wrought-iron coils and jacket, the trunnion piece being welded to the jacket ; (2) the interrupted screw breech closure : (3) the Elswick cup obturator.
It was in the summer of 1879 that Krupp startled artillerists with the most magnificent series of experiments ever witnessed up to that time, the chief event being the trial of the new 40 cmt., 71-ton gun. This was a jacketed gun, made of crucible cast-steel, forged under the hammer, and weighed 71 tons ; length of bore, 21.8 calibers. With a charge of 4s5 lbs. of prismatic black powder, and a 1.715-lb. projectile, a velocity of 1,702 foot-seconds was recorded with tons pressure. The accuracy of the gun was remarkable ; six shots were placed within a vertical rectangle measuring less than 18 in. in height by 71 in. in width. In 1881, Krupp made guns 35 calibers in length, Fig. 1, all of which had a jacket in which was lodged the cylindro-rismatic wedge, the heavier calibers being hooked to the muzzle. The shot chamber (b), which was cylindrical, is now conical, and slopes into the bore grad ually ; the rifling has an increasing twist of from 50 to 25 calibers, instead of the former uniform twist of about l5 calibers.
Before the close of 1881 some 8-in. guns, entirely of steel, were under way in England, their form being a heavy steel tube supported by steel coils. Objections being raised to this method, there was another investigation into the subject of gun construction, which resulted in the following : (1) The breech screw should engage in the jacket ; (2) the hoops should be carried well forward, and be made as iong as was consistent with certainty of manufacture ; (3) forged steel should be used ; (4) steel to be open-hearthed, well tempered and annealed ; (5) the De Bange obturator, shown by Fig. 4, should be used. The wire-wound system was found to possess certain important advantages, and designs for this type were ordered.
In those days the use of liners was quite general for the prevention of erosion, and a tube was used in continuation of the liner to the muzzle. As numerous guns have been put out of service through the splitting of the liners, the system as thee adopted was not found entirely satisfactory. The locking of the joints was accomplished in this way : Take, for example, the locking joint between the jacket and the tube. The former is prepared at the forward end with a row of projections on its inner surface, and the tube is in like manner prepared with a row of projections on its outer surface. In the operation of shrinking on, the projections of one part pass between those on the other, and the jacket is then turned until they are in line, when the intervals are filled in by wedges driven under pressure. In
the 16.25-in. gun longitudinal strength is provided by shoulders, and movement of the tube is prevented by shrinkage, assisted by a ring of yellow metal run into grooves near the front end of the jacket. This device is repeated near the front end of the thrust collar hoop.
In 1881-82, desius were prepared in France for gulls of all service calibers from 65 mm. to 34 cult. inclusive, in which the length of bore, save in a few guns intended for special purposes, is increased to 28 calibers. These guns constitute the 1881 model, and are the most approved pattern actually in service; they are hooped, but not tubed, and the material used tbioughout is steel, forged and oil tempered. The chamber is of much greater diameter than formerly, and the final twist of the rifling is increased from 4° to 7°. While all the parts unite to resist the transverse stresses, the longitudinal stress is borne by the tube alone. Certain difficulties having developed with large guns built after the 1881 model, notably in obtaining an equable temper in the large masses of steel called for by the design, a new design was proposed for the 27 mt. and superior calibers. These guns are tubed, a sleeve screws onto the rear of the tube for the breech plug ; the tube is hooked to within about 8 calibers of the muzzle ; a jacket about 16 calibers long is shrunk over the first layer, and is in turn reinforced with a second layer of five hoops, one of which carries the trunnions.
The heaviest guns in existence are the four Krupp 119-ton guns, of in. caliber, made for the Italian government and designed in 1882. The terms of the contract required that one gun of the four should fire at least fifty rounds with projectiles of 2,028 lbs. weight, to which should be given a muzzle velocity of 1,804 foot-seconds. Ten of the fifty rounds were to be fired at a target 2,734 yards distant, and it was stipulated that all of the shot should fall within an area 10 66 ft. square, The firing was continued up to eighty two rounds, the pressure rising to tons, with a velocity of 1,86 foot-seconds.
The above construction of ordnance is practically what obtains to-day in foreign gun shops. The question of larger calibers has boon brought up and decided against. The 111-Lon English guns were made by contract for home conunnption, and there were grave faults of design developed in the trials which the makers are now trying to remedy by partial reconstruction- As to the question of necessity, the 16-in, gun is required to give at battle ranges, and occasionally at long ranges, the penetrative power and destructive effect which is lacking in the 12 and 13-in. calibers. The striking energy of the 16-in, gun is about 2.4 times that of the 12 in., and its penetration at five miles is equal to the 12-in, at one mile. British vessels carry 34 guns. French 5-1, Italian 40, none of which are less than in. A naval estimate of the highest power guns required cannot, however, be accepted as a standard, as the hind defenses should avail themselves of their advantages over ship carrying capacity, and maintain at all times their natural superiority over naval arma ment. The ships are limited for space. and especially by weight—objections which in themselves are minor matters in shore defenses.