Page:EB1911 - Volume 17.djvu/262

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MACHINE-GUN
247


in one second, and to press the trigger and remove the finger or thumb instantly, and at the same time be ready to traverse to a fresh target, requires considerable skill. The result of these difficulties is that the target when struck is often riddled with bullets when one would have sufficed. The aiming of the gun, when rapid fire is taking place, may also be difficult even on firmly fixed mountings, owing to vibration. The greater delicacy of the modern machine gun has been alluded to above.[1] Nevertheless the advantages of safety, steadiness and lightness which the automatic weapon possesses, have ensured its victory over the older type of weapon, and although the simple strong and well-tried Gatling still has its advocates, every civilized army has adopted one or more of the automatic types.

Organization and Tactical Employment[2]

Although machine-gun tactics are still somewhat indefinite, at least there are well-marked tendencies which have a close relation to the general tactical scheme or doctrine adopted by each of the various armies as suited to its own purposes and conditions. For many years before the South African and Manchurian wars, the machine-gun had been freely spoken of as “a diabolical weapon before which nothing could live,” but this did not contribute much to the science of handling it. Most military powers, indeed, distrusted it—actuated perhaps by the remembrance of the vain hopes excited by the canon à balles. It was not until the second half of the war of 1904–05 that the Japanese, taught by the effective handling of the Russian machine-guns at Liao-Yang, introduced it into their field armies, and although Great Britain had provided every regular battalion with a Maxim-gun section some years before the Boer War, and a Volunteer corps, the Central London Rangers (now 12th bn. London Regiment) had maintained a (Nordenfeldt) gun section since 1882, instruction in the tactics of the weapon was confined practically to the simple phrase “the machine-gun is a weapon of opportunity.” More than this, at any rate, is attempted in the drill-books of to-day.

One important point is that, whether the guns are used as an arm, in numbers, or as auxiliaries, in sections, they should be free to move without having to maintain their exact position relatively to some other unit. It was in following the infantry firing lines of their own battalion over the open that the British Maxims suffered most heavily in South Africa. Another of equal importance is that the machine guns must co-operate with other troops of their side in the closest possible way; more, in this regard, is demanded of them than of artillery, owing to their mobility and the relative ease of obtaining cover. A third factor, which has been the subject of numerous experiments, is the precise value of a machine-gun, stated in terms of infantry, i.e. how many rifles would be required to produce the fire-effect of a machine-gun. A fourth—and on this the teaching of military history is quite definite—is the need of concealment and of evading the enemy’s shrapnel. These points, once the datum of efficiency of fire has been settled, resolve themselves into two conclusions—the necessity for combining independence and co-operation, and the desirability of Mercury’s winged feet and cap of darkness for the weapon itself. It is on the former that opinions in Europe vary most. Some armies ensure co-operation by making the machine-gun section an integral part of the infantry regimental organization, but in this case the officer commanding it must be taught and allowed to shake himself free from his comrades and immediate superiors when necessary. Others ensure co-operation of the machine-guns as an arm by using them, absolutely free of infantry control, on batteries; but this brings them face to face with the risks of showing, not one or two low-lying gun-barrels, but a number of carriages, limbers and gun teams, within range of the enemy’s artillery.

French experiments are said to show that the fire-power of a machine-gun is equal to that of 150–200 rifles at exactly known range, and to 60-80 rifles at ranges judged by the French “instantaneous range-finder.” The German drill-book gives it as equal approximately to that of 80 rifles on an average. The distinction of known and unknown ranges is due to the fact that the “cone of dispersion” of a large number of bullets in collective infantry fire is deeper than that of machine-gun fire. The latter therefore groups its bullets much more closely Fire Effect. about the target if the latter is in the centre of the cone—viz. at known ranges—but if the distance be misjudged not only the close central group of 50% of the shots, but even the outlying rounds may fall well away from the target. At 1500 yards range the “50 per cent. zone” with the Maxim gun is only 34 yards deep as compared with the 60 yards of a half-company of rifles.[3] The accuracy of the gun is more marked when the breadth of the cone of dispersion is taken into account. The “75 per cent.” zone is in the case of the machine-gun about as broad at 2000 yards as that of collective rifle fire at 500. At the School of Musketry, South Africa, a trial between 42 picked marksmen and a Maxim at an unknown range at service targets resulted in 408 rounds from the rifles inflicting a loss of 54% on the enemy’s firing line represented by the targets, and 228 rounds from the Maxim inflicting one of 64%. Another factor is rapidity of fire. It is doubtful if infantry can keep up a rate of 12 rounds a minute for more than two or three minutes at a time without exhaustion and consequent wild shooting. The machine-gun, with all its limitations in this respect, can probably, taking a period of twenty or thirty minutes, deliver a greater Ranging. volume of fire than fifty rifles, and assuming that, by one device or another (ranging by observing the strike of the bullets, the use of a telemeter, or the employment of “combined sights”) the 75% cone of bullets has been brought on to the target, that fire will be more effective. The serious limiting condition is the need of accurate ranging. If this is unsatisfactory the whole (and not, as with infantry, a part) of the fire effect may be lost, and if the safe expedient of “combined sights”[4] be too freely resorted to, the consumption of ammunition may be out of all proportion.

The vulnerability of machine-guns is quite as important as is their accuracy. At a minimum, that is when painted a “service” colour, manœuvred with skill, and mounted on a low tripod—in several armies even the shield has been Vulnerability. rejected as tending to make guns more conspicuous—the vulnerability of one gun should be that of one skirmisher lying down. At a maximum, vulnerability is that of a small battery of guns and wagons limbered up.

Mobility comes next. The older patterns of hand-operated guns weighed about 90 ℔ at least, without carriage, the earlier patterns of Maxims (such as that described in detail above) about 60 ℔. But the most modern Maxims Mobility. weigh no more than 35 ℔. Now, such weapons with tripods can be easily carried to and fro by one or two men over ground that is impracticable for wheeled carriages. Nevertheless,

  1. At San-de-pu 1905 the Japanese machine-guns (Hotchkiss) sustained damage averaging, 1 extractor broken per gun, 1 jam in every 300 rounds. It should be mentioned, however, that the machine-gun companies were only formed shortly before the battle.
  2. In field operations only. For siege warfare see Fortification and Siegecraft.
  3. For practical purposes in the field, the “effective” beaten zone, containing 75% of the bullets, is the basis of fire direction both for the machine-gun and the rifle. The depths of these “effective” zones are on an average:—
      At 500 yds. 1,000 yds. 1,500 yds. 2,000 yds.
    S.L.E. Rifle   220 yds. 120 yds. 100 yds.
    Maxim Gun   150 yds. 70 yds. 60 yds. 50 yds.
  4. “Combined sights” implies firing with the sights set for two different ranges, the usual difference being 50 yds. With grouped machine guns, “progressive fire” with elevations increasing by 25 yds. is used. This artificially disperses the fire, and therefore lessens the chance of losing the target through ranging errors. One ingenious inventor has produced a two-barrelled automatic, in which the barrels are permanently set to give combined elevations. The British memorandum of August 1909 seems to regard the facility of employing combined sights as the principal advantage of the battery over the section.