



RIFLE, OR RIFLED. 



RIFLE, OR RIFLED. 



oo 



directed to the right of the tangent of the trajectory, and there will 

 be increased deflection to the right. 



These effects may be proved experimentally with the gyroscope. It 

 ii, therefore, better, as the derivation when the axis of rotation remains 

 parallel to its original direction is pretty constant for the same dis- 

 tances, to allow for it when laying the gun, than to try and correct it 

 by the form of the shot. 



Another curious effect arising from the action of rotation, tending to 

 keep the axis of rotation parallel to ita original direction, is, that at 

 certain low elevations the range of the elongated projectile is absolutely 

 greater in the atmosphere than it would be in vacuo. This is evidently 

 a point of great importance practically. It is thus explained by 

 Sir W. Armstrong : " In a vacuum, the trajectory would be the same, 

 whether the projectile were elongated or spherical, so long as the 

 angle of elev.-.tion and the initial velocity were constant; but the 

 presence of a resisting atmosphere makes this remarkable difference, 

 that while it greatly shortens the range of the round shot, it actually 

 prolongs that of the elongated projectile, provided the angle of elevation 

 do not exceed a certain limit, which in my experiments I have found 

 to be about 6*. This appear? at first very paradoxical, but it may be 

 easily explained. The elongated shot, if properly formed, and having 

 a sufficient rotation, retains the same inclination to the horizontal 

 plane throughout its flight, and consequently acquires a continually 

 increasing obliquity to the curve of ita flight. Now the effect of this 

 obliquity a, that the projectile is in a measure sustained upon the air, 

 just a* a kite is supported by the current of air meeting the inclined 

 t urface, and the result is, that iU descent is retarded so that it has time 

 to reach to a greater distance." 



The following example, to prove the truth of this statement, is 

 token from Elementary Lectures on Artillery, K. M. Academy,' 

 by Major Owen, K.A. , and Captain Dames, K.A., from which also some 

 of the figure* are taken : " The initial velocity of the projectile from 

 Sir W. Armstrong's 12-pr. gun us said to be 10SO feet per second ; what 

 would be it* range in vacuo when fired at 2 of elevation ? 



B = 



Vx sin2a _ rd5ojj<jin 4 s IK 



9 



- 2515 ft or 838 yds. 





If 1100 be taken as the velocity, 880 yards would 1* the range. 

 the table of ranges given in the ' Manual of Artillery Exercises,' 

 980 yards is the range obtained with this gun at an angle of 2 of eleva- 

 tion. The range of the projectile in the air exceeds therefore that in 

 vacuo by about 140 yards, if the initial velocity is 1080 feet a 

 second, and by 100 yards should the velocity be 1100 feet a second." 

 A 32-pr. shot fired at an angle of 2* with a velocity of 1600 feet per 

 second, ranges lew than | of the distance it would range in vacuo. 



The interior of a rifle barrel is a cylinder, with a certain number of 

 groove* cut in it ; these grooves are parallel to one another, but make 

 an angle with the axis of the cylinder or barrel that is, they are din- 

 posed spirally round it. The bullet fitting these, when forced through 

 the barrel by the action of the powder, acquires a motion of rotation 

 i the axis of the piece in addition to the motion of translation, 

 and this motion it of course retains after leaving the piece. The rifle 

 barrel is in fact a female screw, and the action is the same as that of 

 a nut through which a screw is driven by pressure. 



The clement* of a rifle may be considered to be a cylinder, grooves, 

 tuillft, and method of making the bullet fit the grooves or take the 

 rifling. No rules for those various poinU have at present, at all events, 

 been established ; though perhaps Mr. Whitworth in his experiments 

 has done more than anyone else to establish some of them on a scientific 

 basis. But at present the diameter of the cylinder, that is, the bore ; 

 the number, and depth, and inclination of the grooves ; the form and 

 weight of the bullet, ami the method of making it take the rifling vary 

 with every nation, and indeed with almost every gunmaker. We can 

 therefore merely attempt to give some description of one or two of the 

 most general forms of rifle. Before doing so, however, it may be as 

 well to consider what are the points to be borne in mind, or what are 

 millions of the problem of constructing a perfect rifle. This 

 will awiirt us in coming to a conclusion a* to what rifle combine* the 

 before-mentioned dements in the best proportions. 



lit. The action of a rifle being the same a* that of a nut on a screw 

 driven through it, the action of the powder on a bullet in a rifle barrel 

 matt be the same as that of a pressure moving a body up an inclined 

 plane, the direction of the pressure being parallel to the base. The 

 greater the inclination of the plane, the les* the velocity in the direction 

 of the pressure generated in the body in it* passage over a given space 

 in the same direction, because of the greater inclination of the plane 

 and also because of its thereby increased friction. 



In the rifle, therefore, the greater the inclination * of the groove* 



The Inclination of the groove", commonly cl!nl the twiat, i* generally 

 giTen M one torn la >o many fret. Thl of COUTH- gi\r< no information directl) 

 u to UM proportionate inclination of the groove* In two rifle* of different calibre 

 To* comet estimate of thU, la the angle of inclination of the line, showing 

 the ITTOOTC on the An<lop*4 surface of the borr of the piece, that in, by com 

 paring the length* la which on* tarn i< effected with the circumference* of the 

 ken*. This *y eully be done, when we know the calibre* or bore*, by 

 laying off on a line the length la which one turn or twlit U completed, then 



;he less will be the initial velocity due to a given charge. Hence the 

 inclination of the grooves should be the least that will effect the 

 purpose ; that is, that will give the bullet sufficient rotation round its 



ixis to retain it parallel to its original direction during its flight. This 

 inclination, as given in ' Straith's Artillery,' by Cook and Hyde, is 



Enfield 1 19' 11" 



Jacob's 2 30' 0" 



Whitworth's 4 3' 0" 



With respect to the form to be given to the grooves in section, and 

 their number, it is evident that the main consideration on which they 

 depend is the manner in which the projectile takes its rifling. If it is 

 by the expansion produced by the explosion, it is evident that they 

 should be wide and shallow, rounded and not angular, while the 

 groove or furrow on one side is opposite the projection or land on the 

 other side. The Enfield rifle, described further on, with its three wide, 

 shallow, rounded grooves, fulfils these conditions. If on the other 

 hand the projectile takes its rifling by being forced into a narrower 

 bore, as in the breech-loaders, it is evident that the cutting portions, the 

 lands, should be narrow, the grooves not very deep, not deeper than 

 will just suffice to give a sufficient hold, with sharp angles and square 

 sides at least on one side. The Armstrong gun [RIFLED ORDNANCE], 

 with its numerous narrow lands and furrows, is made in this way. 



If the projectile is formed to fit the grooves for convenience in load- 

 ing, they and the projections on the projectile to fit them should be 

 made prominent and well marked, as in the two-grooved rifled 

 Jacob's or Whitworth's. This last mentioned form, however, is also 

 well adapted for an expanding ball, and while it gives a perfect hold on 

 the projectile reduces friction to a minimum. 



2nd. The picket should be as long in proportion to its diameter as 

 possible; for, caterii paribus, the longer and thinner the projectile is, 

 the greater will be its range and accuracy. But at the same time it 

 must be remembered that, first, especially for military rifles, there are 

 great objections to a very small bore and attenuated picket : the former 

 being difficult to clean, the latter liable to injury, and requiring a long 

 fragile cartridge. Secondly, the inclination of the grooves is necessarily 

 increased, in order to give the picket sufficient rotation ; which, besides 

 being objectionable for the reasons before given, renders the bullet 

 liable to strip, especially with the soft metal required in expanding 

 bullets. Thirdly, the bore may be so diminished as to prevent the 

 power of giving the picket sufficient initial velocity ; that is to say, 

 that, given the calibre, there is a limit beyond which it is detrimental 

 to increase the length and consequent weight of the projectile, ou 

 account of the mechanical distribution of the charge. 



3rd. There are certain mechanical considerations : among which are 

 a barrel of sufficient weight, perfectly true bore, with accurately 

 parallel grooves brought to a high state of smoothness ; and, when the 

 rifling U taken by an expanding bullet, the distribution and depth of 

 the grooves such as will allow of their being perfectly filled. Three 

 wide shallow grooves appear the best, as in the Enfield rifle. Rifles 

 with i/ninin;i ticixli, that is, a spiral increasing in inclination from 

 breech to muzzle, have been tried. In fact the Lancaster rifles, with 

 which the Royal Engineers are armed, are of this description ; these 

 have made good practice, but it may be only from superior manu- 

 facture, fur it is evident that there is nothing gained, but, on the other 

 hand, when the projectile is long, there is a constant alteration of form, 

 causing increased resistance. Thrso various points require a long 

 series of carefully conducted experiments to arrive at any absolute rules. 



Commencing with the greatest weight of bullet, on account of recoil, 

 that it is possible for a man to fire from his shoulder, and investigating 

 how far the greatest advantage in each direction may be obtained, 

 compatibly with the conflicting considerations, is the only manner in 

 wliioli a perfect ritle can be formed. We believe that this is the 

 manner in which Mr. Whitworth arrived at his proportions, and his is 

 certainly the most perfect weapon yet produced. 



The first form of rifle employed in the British service was a BCVCU- 

 groove rifle. The method of loading was this : after pouring in the 

 requisite charge, a greased patch (a circular piece of cotton, about twice 

 the diameter of bore) was placed on the muzzle ; a spherical bullet, 

 slightly larger than the bore of the gun, was then placed on it .ami 

 forced down with an iron ramrod and wooden mallet. Thus the portion 

 of the bullet in contact with the bore became indented, and received its 

 rifling ; it was, however, a long and tedious process, not well adapted 

 for military purposes. It was superseded by the two-grooved rifle and 

 belted ball ; the grooves were wide and deep, and the bullet, which 

 was sewn into a thin piece of calico, had a projecting zone fitting them. 

 Thi* form was easier to load, and gave pretty good practice up to 

 300 yards, but it had the disadvantage of windage, and after a time 

 j . .:"!. 



Robins had pointed out the advantages of a breech-loading rifle, in 

 giving ease in loading : " As both these methods of charging at the 

 mouth take up a good deal of time, the rifled barrels which have been 

 made in England (for I remember not to have seen it in any foreign 



taying off at right angle* to this the circumference of the 1-oro. Completing the 

 rectangle gives the developed imrface, of which the diagonal i* the groove, and 

 the angle it makes with the aide of the rectangle, the angle of inclination. 



