In the Ochta trials the first two projectiles used were of poor quality, but the last three were excellent, and a comparison with their performance against a Vicker's plate and the Schneider steel plate at Annapolis shows that in the former the points of the three projectiles penetrated 7,11, and 4 in. beyond the back of the plate, while in the latter the penetrations of the four 6-in. projectiles beyond the back of the plate were respectively 2.75, and in. Against the nickel-steel 10-in. plate the Iloltzer 6-in. shot first fired penetrated 9 in., and rebounded, broken in two ; the second penetrated 8 in., and rebounded, broken in three pieces; the third went in 114 in., and rebounded unbroken; while the fourth entered 9.1 in. and broke in two. The first at the compound plate entered 13.2 in. and remained entire in the hole ; the second did likewise; the third perforated plate and hacking, and was found unbroken 817 yards to the rear ; and the fourth was intact 938 yards to the rear. The two nickel-steel plates differed somewhat in constitution, containing unequal proportions of nickel, which will account for the different effect npon the projectiles.
The most important struggle between armor and projectiles in this country took place in 1891 at the new naval proving grounds at Indian Head, on the Potomac River. In this the plates were of domestic manufacture, and a portion of the projectiles used were also made in this country. Six plates were used, four 6-in. and one 8-in. projectile being fired at each plate under circumstances similar to the trials already referred to. The general result to the projectiles was in the main like that of the trials at Annapolis. and a positive proof was given of our ability to improve on original designs and to obtain in this country all the armor-piercing shell that we need.
The Carpenter projeetiles are made of chrome-steel, after the Firminy process; that is, all of the patents covering that process were purchased for use in this country ; but something better was expected, as the conditions of the armor were changed first from steel to nickel steel, and then from the ordinary methods of hardening to the adoption of the Harvey system. Consequently experiments were started in hardening the head of armor-piercing shell, and departures were as a natural sequence found necessary. The tempering does not run to the same extreme throughout the shill, as the thinner walls about the powder chamber would not stand the treatment and maintain the desired degree of efficiency ; the head, and as far down as the chamber will admit, are treated, and the projectiles have thus far answered every demand. They are delivered in lots of 100 each, two out of every lot being taken as samples.
Common steel shell are being made by two different processes, one in which they are pressed into shape by means of dies, and the other by the use of electric welding. In the former the shell are made from a cylindrical billet of steel, which is heated and put through a series of dies and presses, which hollow it, draw the sides of this cup-shaped hollow to form the powder chamber, point it, leaving a hole at the apex for the insertion of the fuze ; shape the powder chamber inside; and when the operation is finished nothing remains but to cut the screw-thread for the receipt of the fuze. These projectiles can be turned out in any
quantities desired, and at a far less cost than the armor-piercing type which are turned by machinery. The method above described has been in use abromi for some years, but the machinery as adopted in this country has undergone considerable change from the original.
The Wieder-Sterling Shell.—A new armor-piercing steel shell, named the Wheeler-Ster ling, and hardened by a process that is at present kept a secret, has recently given such excellent results that a number of the projectiles are being made for naval use. A 6-in. shell, weighing 100 lbs., was recently fired through a high-carbon steel armor plate 114, in. thick. shortening after this severe ordeal was but 0.38 in., and the enlargement 0.23 in. The point was not at all distorted, nor was there a scratch to mar the surface from point to base. This is the first American armor-piercing shell made after an American patent and process, and the result is quite remarkable.
Rapid-fire Frojeetiles.—The projectiles for rapid-fire artillery, besides being made by the well-known methods of making shell arid shrapnel, are now made also by the electric welding process. Iron tubing is cut in suitable lengths, and to this are welded steel heads and bases. Experiments on the proving ground with projectiles of this type have proved them to be well adapted to the purpose ; and it is now thought that the larger-calibered shell for ordinary service can be made by the same method. The rapidity and compara tive cheapness with which shells made in this way can be turned out recommend the pro cess, which, at present, bids fair to displace all other methods of manufacturing ordinary shell and shrapnel for quick-fire guns. (See WELDING, ELECTRIC.) Hotchkiss Projectiles.—The Hotchkiss guns are furnished with ammunition made espe cially for their guns, and it is of three kinds : Cast-iron shell, steel shell, and case-shot. The two former have the same general appearance, and are of the cylindrical ogival type ; the point of the steel shell is sharply pointed, and the fuze is inserted in the base ; the cast iron shell has a percussion fuze fitted to the front end, which is truncated to form a seat. A number of grooves are cut around the body of the projectile, and over these is forced a sheet brass belt. When the gun is fired this belt is forced into the grooves, and gives the rifling motion to the projectile. Both classes of shell are shaped with great care and turned true : those of steel are tempered. The case-shot consists of a shell of thin brass filled with lead balls, the intervening spaces being filled with sawdust.