The actual degree of velocity, as judged by the range of fire at which an injury is received and the resulting injury, is very hard to estimate on account of the many and varying factors which enter into its determination. The mere recital of some of these will suffice to make this evident.
1. Quality of the individual cartridge employed, as to loading, the materials employed, and their condition.
2. The condition of the rifle as to cleanliness, heating, and the state of the grooves of the barrel.
3. The angle of impact of the bullet with the part injured.
4. Resistance dependent on the weight of the whole body of the man struck, or of an isolated limb.
5. Special peculiarities of build in the individual struck, such as thickness and density of the integument and fasciae, strength and thickness of the bones, &c.
6. State of tension of the muscles, fasciae, and ligaments at the moment of impact, and fixity or otherwise of the part of the body struck.
7. The degree of wind, temperature, and hygroscopic conditions of the atmosphere.
These form some of the more important points which have to be taken into consideration, in addition to a mere calculation of the actual distance from which a wound has been received from a particular rifle, and taken with the unsatisfactory nature of the evidence as to the latter, which is usually alone obtainable, it is clear that definite a.s.sumptions are scarcely possible. In a great number of cases I came to the conclusion that the only indisputable evidence of low velocity was the lodgment of an undeformed bullet. There is little doubt, moreover, that the general tendency of wounded men was to minimise the range of fire at which they were struck, and again that in the majority of cases in this campaign it was quite impossible to determine whence any particular bullet had come, since the enemy was seldom arranged in one line, but rather in several.
Again, smokeless powder was generally employed. Beyond this, in some cases where there was no doubt of the short distance from which the bullet was fired, the wounds were due to "ricochet" of portions of broken-up bullets. The following instance well ill.u.s.trates this. A sentry fired five times at two men within a distance of six paces, knocking both down. One man received a severe direct fracture of the ilium, the bullet entering between the anterior superior and inferior iliac spines and emerging at the upper part of the b.u.t.tock. The entry and exit apertures were large but hardly "explosive," as a subcutaneous track four to five inches long separated them. Besides this both men had other lesser injuries; thus in the second two perforating wounds of the arm existed. The latter were not unlike type Lee-Metford wounds, and were regarded as such until a few days afterwards when a hard body was felt in the distal portion of one track and removed. This proved to be a part of the leaden core only, and the similar wound had no doubt been produced by a like fragment, the bullet having broken up on striking the stony ground.
_Trajectory._--The comparative flatness of this depends on the construction of the rifle and the propulsive force employed, and varies as does velocity with the nature, excellence, and amount of the explosive, the correctness of the principles upon which the bullet is devised, and the mechanical perfection of its manufacture. Its importance naturally consists in the manner in which it affects the possibility of covering objects on a wide area of ground and thus creating a broad "dangerous zone." A bullet fired on level ground from any one of three of the rifles referred to later (Lee-Metford, Mauser, Krag-Jorgensen), sighted to 500 yards and fired from the shoulder in the standing position, will cover some part of an erect man of average height during the whole extent of its flight. A body of men within that distance is therefore in a position of extreme peril in the face of a good shooting enemy.
The importance of a flat trajectory is progressively lost, however, with any rifle, as the weapon is gradually sighted to greater distances. Thus when sighted to 2,000 yards the bullet from the Lee-Metford rifle rises 174 feet, and a whole army might comfortably be situated over a considerable area within that distance. The importance of flatness of trajectory is also influenced by the nature of the ground occupied by the combatants. Thus when the area to be covered consists in ground first rising then falling from the rifleman, the trajectory will become more or less parallel to the surface crossed, and the "dangerous zone"
will be correspondingly increased in extent. On the other hand, when the ground slopes away from the rifleman the rise of the projectile is exaggerated, and reaches its most limited capacity of covering an intervening s.p.a.ce when the flight crosses a hollow.
_Revolution of the bullet._--It only remains in this place to say a few words concerning the revolution imparted to the bullet by the rifling of the barrel. This ensures the flight of the projectile on a line parallel to its long axis, and notably increases its power of penetration.
Both these properties of the flight are to the advantage of the wounded, since, as already mentioned, the more exactly the impact corresponds to a right angle with the skin, the more limited will be the area of contusion, even if it be of the most severe character, while to the twist of the bullet must be ascribed a not inconsiderable part in the explanation of the ready and neat perforations of narrow structures which are frequently produced.
It has been pointed out that the Lee-Metford bullet turns on its own axis once in a distance of ten inches, while the Mauser revolves once in a distance of eight and eleven-sixteenths inches; hence not more than at most two revolutions are made in tracks crossing the trunk, and not more than half a full revolution in the perforation of a limb. None the less, no one can deny the influence of the one half turn of supination in entering a perforating tool of any description, both as preventing splintering, and in preserving the surrounding parts from damage.
Beyond this, the spiral turn of the bullet, by diverting a part of the transmitted vibrations into a second direction, must, in the case of wounds of the body, help to throw off contiguous structures, and while those that are in actual contact are more severely contused, the surrounding ones suffer somewhat less direct injury. It must be borne in mind, also, that rapidity of revolution does not fall _pari pa.s.su_ with that of velocity of flight, but that the former undergoes a comparatively slighter diminution until the bullet is actually spent.
Hence, the influence of revolution is felt, however low the velocity may be, provided sufficient striking force is retained to enter the body. A word must be added here as to the surface of a discharged bullet; this, in taking the rifling of the barrel, becomes permanently grooved. The depth of the groove differs with the variety of rifle. In the Lee-Metford the grooves are deep (.009), in the Mauser slightly less so (.007), but the surface of both bullets is comparatively roughened when revolving in the body, and this circ.u.mstance, since the projectile exactly fits its track, may influence the degree of the surface destruction of tissue, and somewhat aid in the clean perforation of bone, since a little bone dust is always found at the entrance aperture of a ca.n.a.l in cancellous bone.
During the campaign many varieties of rifle projecting bullets of widely differing calibre were employed by the Boers, many of whom as sportsmen preferred the rifle to which they were accustomed to a regulation weapon, and an ill.u.s.tration of a large variety of bullets from cartridges which I collected from a.r.s.enals and camps is given below (p.
96). The great majority of the men, however, were armed with small-calibre weapons of some sort, and as the wounds produced by these are of chief interest at the present day, I shall say little of any others, beyond an occasional reference to Martini-Henry rifle wounds which may be considered to represent approximately those made by large leaden sporting bullets.
[Ill.u.s.tration: FIG. 14.--Type Cartridges in common use during the war.
From left to right: Martini-Henry, Guedes, Lee-Metford, (Spanish) Mauser, Krag-Jorgensen]
The most important, as the most frequently employed, rifles projecting small-calibre bullets were the Krag-Jorgensen, Mauser, Lee-Metford, and Guedes, given in the order of increase of calibre (from 6.5 to 8 millimetres, or .254-.314 in.) in the bullets. As to the seriousness of wounds produced by these there is little to choose, differences in character being only those of degree. Such differences depended on the area of tissue implicated, corresponding with the calibre of the particular bullet, the comparative weight of the bullet, and the degree of velocity of flight maintained at the moment of impact. When, however, any of these bullets have been exposed in their flight to influences capable of causing deformity of their outline and symmetry, peculiarities of construction and in the composition of the metals employed in their manufacture may materially alter the character of the wounds produced and revolutionise a cla.s.sification founded purely on the relative weight, calibre, and degree of velocity with which each is endowed.
TABLE I
[Transcriber"s note: table split to fit on page.]
+-------------------+----------------+------------------+----------------+ | | Martini-Henry | Guedes | Lee-Metford | +-------------------+----------------+------------------+----------------+ |Calibre of rifle | .45 in. | .314 in. | .303 in. | |Number of grooves | 7 | 4 | 7 | |One twist in | 22 in. to right|9.85 in. to right | 10 in. to left | |Muzzle velocity | 1,300 f.s. | 1,988 f.s. | 2,000 f.s. | |Sighted to | 1,450 yds. | 2,600 paces | 2,800 yds. | |Weight of cartridge| 758 grains |464.05 grains[6] | 416-1/2 grains | |Weight of bullet | 480 grains | 244 grains | 215 grains | |Length of bullet | 1.250 in. | 1.250 in. | 1.250 in. | |Calibre of bullet | .450 in. | .315 in. | .309 in. | |Charge of powder | 85 grains | 20-23 grains | 31-1/2 grains | | | (black powder) | (nitro- | (cordite) | | | | smokeless) | | |Nature of alloy | -- | Mantle: Mild | Cupro-nickel | | used for mantle | | steel, greased | | | of bullet | | | | |Thickness of | -- | -- | Mark II. bullet| | mantle | | | | |Tip | -- | .031 | .036 | |Sides .984 from tip| -- | .011 | .015 | +-------------------+----------------+------------------+----------------+
+-------------------+---------------+--------------------+---------------+ | | Lee-Enfield | Mauser | Krag- | | | | | Jorgensen| +-------------------+---------------+--------------------+---------------+ |Calibre of rifle | .303 in. | .276 in. | .254 in. | |Number of grooves | 5 | 4 | 4 | |One twist in |10 in. to left |8-11/16 in. to right| 8 in. to left | |Muzzle velocity | 2,000 f.s. | 2,262 f.s. | 2,309 f.s. | |Sighted to | 2,800 yds. | 2,187 yds. | 2,406 yds. | |Weight of cartridge| 416-1/2 grains| 384.5 grains | 372.1 grains | |Weight of bullet | 215 grains | 173.3 grains | 156.4 grains | |Length of bullet | 1.250 in. | 1 in. | 1.250 in. | |Calibre of bullet | .309 in. | .280 in. | .260 in. | |Charge of powder | 31-1/2 grains | 38.0 grains | 36 grains | | | (cordite) | (smokeless) |(nitro | | | | | -smokeless) | |Nature of alloy | Cupro-nickel | Mantle: Steel |Mantle: Mild | | used for mantle | | with alloy of | steel coated | | of bullet | | copper on | with copper | | | | surface | nickel, the | | | | | composition of| | | | | the latter | | | | | being that of | | | | | the cupro- | | | | | nickel of the | | | | | Lee-Enfield | | | | | bullet | |Thickness of |Mark II. bullet| -- | -- | | mantle | | | | |Tip | .036 | .031 | .022 | |Sides .984 from tip| .015 | .015 | .015 | +-------------------+---------------+--------------------+---------------+
Some particulars of the four rifles and their projectiles are collated in Table I., to which is added the corresponding information regarding the Martini-Henry for the purposes of comparison.
TABLE II.--PENETRATION
The penetration of the Martini-Henry and the Lee-Metford or Lee-Enfield rifle with Mark II. bullet is as follows:
Martini-Henry 15-1/2 in. of 1 in. deal boards 19 in. of sand 1 in. apart containing 15 per cent. of moisture
Lee-Metford {Mark II.} 42 in. of 1 in. deal boards 60 in. of sand Lee-Enfield {bullet } 1 in. apart containing 15 per cent. of moisture
The penetration of bullets of .314 calibre differs little from that possessed by the Lee-Metford or Lee-Enfield, of which the muzzle velocities are very little lower, with Mark II. bullet. The Belgian Mauser perforates 55 inches of fir-wood at 12 metres distance. With regard to the penetration of bullets of smaller calibre that of the Roumanian Mannlicher (.256) may be taken as typical. When fired into a sand b.u.t.t at 25 yards the bullet enters 9 inches and then breaks up.
The comparative size of the different cartridges is shown in fig. 14.
The general remarks already made as to the effect of weight, calibre, and velocity sufficiently explain the importance of the particulars given in this table, but it will be noted that the Lee-Metford rifle is inferior to both the Krag-Jorgensen and Mauser rifles in the initial velocity transmitted to its bullet. The tendency to equalisation, in this particular, when the remaining velocity is considered, has been mentioned; but it may be of interest if I quote from Nimier and Laval[7]
the scale on which the decrease in velocity takes place in the case of the three weapons.
METRES PER SECOND
+---------------------+-------------+--------+----------------+ | | Lee-Metford | Mauser | Krag-Jorgensen | +---------------------+-------------+--------+----------------+ | | | | | | Initial velocity | 630 | 718 | 720 | | Remaining velocity: | | | | | At 100 metres | 574 | 699 | 718 | | At 1,000 metres | 249 | 264 | 269 | | At 2,000 metres | 159 | 165 | 165.9 | | | | | | +---------------------+-------------+--------+----------------+
Giving full importance to the effects of velocity as a factor in the severity of the injuries produced, when the large proportion of wounds received at distances above 1,000 yards is borne in mind, we see how rapidly the superiority of the smaller projectiles is lost. This loss, even in the early stages, is probably more than made up for in the case of the Lee-Metford, when the superiority in weight, calibre, and bluntness of extremity as contributing to striking force is taken into consideration.
The striking force (kinetic energy) of a bullet is indicated by the following formula: F = 1/2 mv.^{2}; that is to say, the striking force is equal to half the weight of the bullet multiplied by the square of the velocity.
In point of fact, with unaltered regulation bullets I was never able to determine any very material difference between the wounds produced, further than that the wounds of entry and exit in the soft parts tended to correspond with the calibre of the particular bullet concerned.
Although the immense majority of the wounds which came under my notice were caused by the Mauser bullet, yet I saw some hundreds of wounded Boers and a good many of our own men wounded by Lee-Metford bullets, in the latter case no doubt by some of the sporting varieties. The only cases that I can call to mind or have noted as exhibiting a superior wounding power in the Lee-Metford bullet are some injuries to bone. Thus I saw a considerable number of clean perforations of the patella produced by Mauser bullets, while the only two Boers whom I saw with injured patellae had suffered transverse fractures. Again, I have a lively recollection of an old Boer who had suffered a fracture of the middle third of the femur, in the thigh of whom, with small apertures of entry and exit, a cavity of destroyed tissue, five inches across, was found beneath the fascia lata at the distal side of the fracture. I cannot however say that I did not observe many equally severe injuries to the femur produced by Mauser bullets in our own men, and as far as fractures of the skull went, a somewhat crucial test, among the men brought off the battlefield alive, I never saw any difference in severity whatever.
[Ill.u.s.tration: FIG. 15.--Sections of four Bullets to show relative shape and thickness of mantles.
From left to right: 1. Guedes; regular dome-shaped tip; mild steel mantle; thickness at tip 0.8 mm.; at sides of body 0.3 mm. 2.
Lee-Metford; ogival tip; cupro-nickel mantle; thickness at tip 0.8 mm.; gradual decrease at sides to 0.4 mm. 3. Mauser; pointed dome tip, steel mantle plated with copper alloy; thickness at tip 0.8 mm.; gradual decrease at sides to 0.4 mm. 4. Krag-Jorgensen; ogival tip as in Lee-Metford; steel mantle plated with cupro-nickel; thickness at tip 0.6 mm.; gradual decrease at sides to 0.4 mm. The measurements of the sides are taken 2.5 cm. from the tip. Note the more gradual thinning in the Lee-Metford mantle.]
These points of comparison having been made, it only remains to consider one other point, that of the relative stability of the bullets. This is a matter of the greatest importance as regards the regularity or otherwise of the wounding power of the projectile, and, as far as my experience went, I believe the Mauser to far exceed the Lee-Metford in instability of structure.
The core of all four bullets is composed of lead hardened by a certain admixture of tin or antimony, but the mantle differs in composition, thickness both general and in different parts of the bullet, mode of fixation, and consequently in its power of resistance to violence.
Fig. 15 gives an exact representation of the relative thickness of the mantles, and shows the general tendency to a thickening of the mantle at its upper extremity, designed to increase both the stability and striking power of the projectile. It will be noted that in general stoutness the Lee-Metford stands first, as the case increases gradually in thickness from base to apex.
Beyond this it must be noted that the Lee-Metford is the only one of the four that is ensheathed with a mantle composed of a definite alloy, this consisting of 80 parts of nickel and 20 of copper. Two of the remaining bullets, the Mauser and Krag-Jorgensen, are ensheathed with steel covered with a thin coating of an alloy of copper or cupro-nickel, to take the rifling of the barrel, while the third has a plain steel mantle which is covered with a layer of wax to take the place of the nickel used in the manufacture of the two others. It is interesting to mention here that the Boers evidently found the copper alloy coating insufficient for its purpose, or at any rate not satisfactory in preserving the weapon from the ill-effects consequent on the friction between the steel case and the rifling of the barrel, as at about the middle of the campaign they began to use their bullets waxed, as in the case of the Austrian Mannlicher; hence the legend of the poisoned bullets which caused such a sensation for a short period amongst the uninitiated. It is possible also that the additional layer of wax was necessitated by the wearing of the barrel.
The wax employed for the Mauser bullets was not originally green. Mr.
Leslie B. Taylor informs me that it is probably paraffin wax, the green colour depending on the formation of verdigris from the copper alloy with which the steel envelopes are plated. This completely corresponds with my own experience, since on the bullets in my possession the green colour, originally pale, has steadily increased in depth. Many old leaden bullets I found in the Boer a.r.s.enals were also waxed, but in this case no alteration in colour had taken place. The Guedes bullets, which are cased in mild steel, become somewhat brown with exposure from a similar oxidation or rusting of the surface.
As far as my experience went, however, the steel casing has an important surgical bearing beyond the mere question of wear and tear on the rifle barrel. That it possesses elasticity and capability of bending is obvious, and in a later chapter, devoted to irregular wounds, several ill.u.s.trations of such deformities are given; but when it strikes stone I believe it splits and tears with very much greater freedom than the cupro-nickel mantle of the Lee-Metford. At any rate, I never came across Lee-Metford bullets deformed to the same degree as Mauser bullets, either when removed from the body, or as ricochet projectiles on the field of battle. For this reason, therefore, provided the fighting takes place on stony ground, I believe the Mauser bullet and others ensheathed in steel to be much more dangerous surgically than those encased in cupro-nickel. I fancy this would be equally the case even if the mantles were of exactly the same thickness.