388 FIRE-ARMS 



as shown in section, fig. 904, which shows a cylindrical bullet in a hexagonal banvl. 

 The hexagonal bullet, which is preferred to the cylindrical one although (it her 

 may bo used, is shown \nfig. 905. Supposing, however, that a bullet 

 of a cylindrical shape is fired, when it begins to expand it is driven 

 into the recesses of the hexagon, as shown in fig. 904. It thus adapts 

 itself to the curves of the spiral, and, the in- 

 clined sides of the hexagon offering no direct 

 resistance, expansion is easily effected. With 

 all expanding bullets proper powder must bo 

 used. In many cases this kind of bullet has 

 failed, owing to the use of a slowly-igniting 

 powder, which is desirable for a hard metal 

 projectile, as it causes less strain upon the 

 piece ; but is unsuitable with a soft metal ex- 

 panding projectile, for which a quickly igniting 

 powder is absolutely requisite to ensure a com- 

 plete expansion, which will fill the bore : un- 

 less this is done the gases rush past the bullet, 



between it and the barrel, and the latter becomes foul, the bullet is 

 distorted, and the shooting must be bad. If the projectile be made 

 of the same hexagonal shape externally, as the bore of the barrel 

 internally, that is, with a mechanical fit, metals of all degrees of hard- 

 ness, from lead, or lead and tin, up to hardened steel, may be employed, and slowly- 

 igniting powder, like that of the service, may be used. As we have already stated, 

 the Enfield rifle has one turn in 6 ft. 6 in. ; that is, the bullet rotates once on its 

 axis in passing over this space. This moderate degree of rotation, according to 

 Mr. Whitworth, only admits of short projectiles being used, as long ones turn over on 

 issuing from the barrel ; and, at long ranges, the short ones become unsteady. With 

 the hexagonal barrel much quicker turns are used ; and ' I can fire projectiles of 

 any required length, as, with the quickest that may be desirable, they do not " strip." 

 I made a short barrel, with one turn in the inch (simply to try the effect of an ex- 

 treme velocity of rotation), and found that I could fire from it mechanically-fitting 

 projectiles, made of an alloy of lead and tin ; and with a charge of 35 grains of powder 

 they penetrated through 7 inches of elm plauks.' 



' For an ordinary military barrel 39 inches long, I proposed a "45-inch bore, with 

 one turn in 20 inches, which is, in my opinion, the best for this length. The rota- 

 tion is sufficient, with a bullet of the requisite specific gravity, for a range of 2,000 

 yards. The gun responds to every increase of charge, by giving better elevation, 

 from the service charge of 70 grains up to 1,200 grains ; this latter charge is the 

 largest that can be effectually consumed, and the recoil then becomes more than 

 the shoulder can conveniently bear with the weight of the service musket.' 



The advocates of the slow turn of one in 6 ft. 6 in., consider that a quick turn 

 causes so much friction as to impede the progress of the ball to an injurious, and 

 sometimes dangerous, degree, and to produce loss of elevation and range ; but Mr. 

 Whitworth's experiments show the contrary to be the case. The effect of too quick 

 a turn, as to friction, is felt in the greatest degree when the projectile has attained its 

 highest velocity in the barrel, that is at the muzzle, and is felt in the least degree 

 when the projectile is beginning to move, at the breech. The great strain put upon a 

 gun at the instant of explosion is due, not to the resistance of friction, but to the vis 

 inertia of the projectile which has to bo overcome. In a long barrel with an ex- 

 tremely quick turn, the resistance offered to the progress of the projectile as it is 

 urged forward becomes very great at the muzzle, and, although moderate charges 

 give good results, the riflo will not respond to increased charges by giving better 

 elevation. If the barrel bo cut shorter, an increase of charge then improves the 

 elevation. 



There does not appear to have been, even yet, any thoroughly satisfactory 

 ments on the degree of motion which it is necessary to impart to the ball to ensure a 

 flat trajection, and to overcome the different forces which are continually interfering 

 with the correctness of aim, with even the best rifle. In the experiments with Arm- 

 strong's and Whitworth's cannon, some very satisfactory results have been obtained, 

 and much information may be gained by studying the experiments quoted in the 

 article on ARTELLKRY. 



A professional writer, well qualified to jud-- of the matter on which he wrote, has 



made some striking remarks on the Whitworth riflo in the 'Mechanics' Magazine.' 



After pointing out the small importance of a high prime cost in tho case of so 



durable a weapon as tho rifle in question, ho refers to the strength of the metal used. 



In illustration of its great strength, this fact is quoted, Mr, Whitworth put into 4 



