1. DEVELOPMENT OF THE ARM.

The effect of canister had decreased considerably with the introduction of rifled guns, and this was the more noticeable, because, simultaneously therewith, the accuracy and rate of fire of the infantry rifle was greatly increased. The attempts to re-invest the artillery with its one-time superiority were directed in two channels: one aimed at perfecting shrapnel, which had been rather neglected up to this time (England, Prussia, Austria), while the other resurrected the mediaeval idea of the “barrel-organ gun,” with a view of assembling a number of rifle barrels and of combining thereby the accuracy of the small arm with the moral effect of canister. Thus, among others, the 4-10 barreled Gatling gun was invented in America in 1861, it being the oldest representative of this type of weapon. In order to obtain a weapon matching the Prussian needle gun, Bavaria adopted the 4 barreled Feldl gun and France the 25 barreled mitrailleuse.[274] The name canon à balles, which was given the gun, sufficed to indicate the manner in which it was intended to be used. As these guns frequently failed in action, offered the same target and required the same equipment and approximately the same road space as field guns, the states who had first adopted them, finally decided to dispense with them on European theaters of war. The further development of machine guns was not especially accelerated by the fact that the French mitrailleuses had not fulfilled the expectations entertained for them during the Franco-German war, isolated cases excepted,[275] and that they were quickly silenced by the German artillery, which was equipped only with percussion shell, as soon as their position was ascertained. Thus, these guns seemed useful only in colonial wars and on board war ships for warding off torpedo boats. Although they took up very little room when in position, they were not considered useful for flank defense in fortresses, on account of the frequent breakdowns. In addition to their height, other defects developed; for example, they could obtain only a very insignificant rate of fire, betrayed their position by the powder smoke, and lacked the means for ascertaining ranges.

The situation changed entirely when a practicable, smokeless powder was invented, and Hiram Maxim, an American, succeeded in utilizing the energy of the recoil (a factor neglected up to that time, although annoying to the marksman) for opening the breech, inserting a fresh cartridge into the chamber, closing the breech, and automatically firing the piece.[276] Through this invention it became possible to fire a maximum of 900 and an average of 500 rounds per minute, from a single barrel moving laterally back and forth. The desire to obtain a still greater rate of fire was checked effectively, because of the fact that with such an increase the danger of jamming increased and the use of infantry ammunition was precluded. The water in the jacket continues to be a decided drawback to this type of gun, for it is not always easily procured, impairs the mechanism by freezing, makes it difficult to change barrels, and constitutes a considerable weight. If cooling the barrel by means of water were to be dispensed with, the accuracy of the piece would rapidly diminish, and, after 1000 rounds of continuous fire, bullets would tumble even at short ranges. At the present time water is still the most effective means of cooling the barrel.[277]

Machine guns fire ordinary small arms ammunition carried in loops on a canvass belt (weighing 1 kg. when empty), which is generally capable of holding 250 rounds of 8 mm. cartridges weighing 8.315 kg. These belts are very carefully manufactured, the material being shrunk, so as to prevent their shrinking when in use. Two men can refill an empty belt with 8 mm. cartridges in seven minutes, according to Swedish experiments, while a belt filling machine can refill one in a still shorter time. The rate of fire of machine guns is approximately 500 rounds per minute. They are variously mounted,[278] according to circumstances, on sleds (in which the gun rests on a frame similar to that of a wheelbarrow), on tripods, or, for mountain warfare, on basket frames. Although the greatest readiness for firing was obtained with guns mounted on cavalry carriages (two-wheeled carts, similar to limbers, and equipped with shafts), which also permitted the greatest amount of ammunition to be carried along, these guns offered such a high target that their use, in an infantry action, was entirely out of the question, leading only to their being quickly silenced. Another defect was that the guns were unable to follow immediately upon the heels of the organization to which they were attached. Guns mounted on light tripods possess the least readiness for firing, as the gun must be dismounted during each change of position; but tripods are indispensable in mountain warfare. In India a tripod frame on wheels is employed. The basket frame, which is very light and is carried on the back of a soldier, affords nothing but a rest for the gun. This type of mount has the disadvantage of necessitating, in reality, freehand firing when the barrel is supported near the muzzle; that the operator, when firing continuously, becomes greatly fatigued, and that the accuracy suffers in consequence thereof. The advantages of the tripod and the wheeled carriage have been skillfully combined in the carriage adopted in Germany. In this the gun rests on a sled; this is in turn supported by the carriage proper, which is wheeled. In exceptional cases the gun may be fired from the carriage, but ordinarily it is fired from the sled, which is detached from the carriage for that purpose. This sled permits the gun to be laid at any desired height and enables it to follow the infantry anywhere during an action.[279]

Machine guns can be transported upon larger vehicles capable of being unlimbered; they can also be carried on pack horses or other pack animals, and for short distances by men. Although pack animal transportation enables the guns to follow the troops anywhere, the amount of ammunition that can be carried along is limited, and the opening of fire is retarded, since gun and tripod must first be assembled; the opening of fire may even be delayed when a pack animal falls; ammunition cannot be carried on the gun; and the animals get sore backs even if pack saddles are carefully adjusted.

2. THE POWER OF MACHINE GUNS.

The machine gun is noted for its adaptability to any terrain, and the constancy of its high rate of fire as compared with that of a body of infantry, which decreases with the range, the diminishing visibility of the target, and prolonged fire. On the other hand, a single jamming can make a machine gun valueless, at least for the time being. For this reason, the Germans employ machine guns only in platoons, as a rule, and the Swiss let both guns of a platoon fire simultaneously only in exceptional cases. Theoretically, the maximum rate of fire of 600 rounds per minute will rarely be attained; and 200-300 rounds per minute will usually suffice against prone targets. In Germany volley and continuous fire are employed; fire by a single piece is used only to ward off patrols when the machine guns do not want to betray their position.[280]

A volley consists of about 25 rounds and is followed by a pause for observing the effect of the fire. It is employed in adjusting the fire upon difficult targets in rolling country. Fire for effect consists, as a general rule, of “continuous fire,” and is interrupted only when the tactical situation requires it. The water in the jacket should be renewed and oiling attended to during the pauses in the fire, whether these grow out of the tactical situation, or are made necessary by technical considerations.

The fire is either directed upon a point (concentrated fire), the elevation and direction of the piece being fixed, or it is distributed over the entire target or over a designated part of the same (sweeping, and progressive fire).[281]

The ballistic properties of the gun are the same as those of the infantry rifle.[282]

In the machine gun an important factor in the dispersion of infantry fire—flinching and errors in aiming—is eliminated, while the heating of its barrel and the vibrations of its carriage in continuous fire do not produce a corresponding increase in dispersion. On this account the cone of dispersion of the machine gun is more compact than that of the infantry rifle and its accuracy at long ranges is therefore considerably greater than that of the latter.[283] Firing tests indicate that the accuracy of machine gun fire diminishes only very slightly with increasing range, provided the appropriate elevation is used.[284]

In war the influence of the compact cone of dispersion will be still more potent, for we will then have to reckon with a single, specially selected machine gun marksman who is well protected, while the excitement of battle will produce a far different impression upon an organization composed of men differing materially from each other. The compactness of the cone of dispersion of the machine gun requires that the appropriate elevation be used if the fire is to be effective against well concealed prone skirmishers. This can be accomplished only in part by employing range finders. Since the probable error of these instruments is ±5% of the range, this determination is so inaccurate for machine gun fire that nothing remains but to increase the dispersion artificially. When it is impossible to observe the strike of the bullets, the dispersion may be artificially increased by employing combined sights, two in a single platoon and three in a machine gun battery (company), and above all by sweeping. The employment of combined sights would appear to be too rigid a method; sweeping fire is at any rate better.[285]

From general ballistic data, Lieutenant-General Rohne[286] computes that the following results would be obtained by a machine gun and a detachment of skirmishers when firing with the appropriate elevation at a broad target 1 m. high:—

This nearly double superiority is reversed, however, when the appropriate elevation is not used:

From this it follows that the good qualities of the machine gun can be utilized to the fullest advantage only when the appropriate elevation is used. When this is not accurately known, the fire effect of the machine gun drops down to zero more quickly than that of a skirmish line. Where local conditions are at all favorable, the determination of the appropriate elevation is facilitated by observing the strike of the projectiles in “volley fire.”

It is clearly apparent that the permissible error of the range finder is smaller than the depth of the vertical dispersion strip covered by 75% of the bullets.

The difficulty of hitting a target lodged in some feature of the terrain requires that the machine gun be used first of all against large targets that are visible for a short time only. When the appropriate elevation is used, a decisive effect may be confidently counted on within a short space of time; when an inappropriate elevation is used and the fire is not properly observed, only accidental hits can, as a rule, be expected, even when the fire is directed on tall, dense targets. When the fire is directed on skirmishers lying down, the effect produced is not commensurate with the amount of ammunition expended, and a slight error in the elevation used may nullify the effect entirely. A straight line of trenches, which is plainly visible, is, on the other hand, an eminently favorable target. The heating of the barrel, and the difficulty of replenishing ammunition and renewing the water in the jacket, tend to work against a participation of machine guns in a protracted fire fight. The machine gun is not at all suited for carrying on a prolonged fire action.

It is very difficult to determine the relative combat value of a body of infantry as compared with that of a machine gun. One will not be far wrong in placing this value between 50 and 60 men.

In experimental field firing at the Swiss Infantry Musketry School, it was demonstrated that 30-40 skirmishers almost in every case rapidly gained the upper hand over a machine gun in the open, at 900 m., but that the infantrymen had small chances of success when the position of the machine gun could not be accurately determined. In Switzerland a machine gun is considered equivalent to 50 infantrymen. Skirmishers are the most difficult target for machine guns to fight, and, at the same time, they are the most dangerous. When the fire is well observed, a good effect can, indeed, still be counted on, when the fire is directed at prone skirmishers at ranges up to 1000 m., but this is not true when the fire cannot be observed; in the last mentioned case, no effect worth mentioning is produced.

3. INFANTRY VERSUS MACHINE GUNS.

It will rarely be possible to concentrate upon a machine gun battery of six guns a fire equivalent to its own. Because of the small target offered by machine guns, it is necessary for a firing line to concentrate its fire upon one machine gun at a time, thus gradually silencing the battery in detail. This procedure is feasible because it is very difficult for the machine guns to reach with their fire all parts of a well concealed skirmish line. The normal relation, unfavorable for the infantry, changes in its favor, however, as machine guns cannot keep up a high rate of fire for a prolonged period, even when nothing is considered but ammunition supply; as serious breaks are especially apt to occur when the gun is worked to its maximum capacity; and as the ammunition expended in one minute (3600 rounds) cannot produce an effect unless not only the correct range but also the proper elevation is accurately known.

The fight against machine guns may be advantageously conducted according to the following principles:[288]

1. Infantry skirmishers should conceal themselves so well that it will be difficult for the hostile machine gun battery to find them. Color of immediate vicinity (shade) and background should be considered; platoon and other leaders must not stand upright; objects that are clearly visible should be avoided.

2. It should be made difficult for the hostile machine guns to observe their fire (ricochets) and to measure the range. (No prominent features that would facilitate such measurements should be located near the infantry position).

3. The firing line, as far as this is possible, should not be continuous; the several parts of the line should be posted in echelon.

4. Kinds of fire: Lively fire at will should be used.

5. Expenditure of ammunition: At least 600 rounds should be expended against each machine gun.

6. At the outset a single company should concentrate its fire upon a single machine gun, picking out the one that is most clearly visible. Machine guns on the flanks are not good targets, as a strong wind may deflect the fire directed upon them.

The following rules, governing the conduct of infantry when exposed to machine gun fire, may be deduced from the above:

Even skirmish lines cannot continue their advance over terrain devoid of cover, when exposed within a range of 1500 m. to the unsubdued fire of machine guns; nothing remains but for them to lie down, and to gain ground to the front in groups, or one by one.

The same is true of route columns. They can only deploy to the right and left front at double time, and take cover.

The most unsuitable formation under machine gun fire is the column of platoons, whether lying down or in motion.[289]

If the column of platoons is reached by effective machine gun fire, when lying down, line must be formed. The men must not rise, however, to execute this movement, but the platoons should crawl forward into line. For the men to rise would mean annihilation.

The low target offered by machine guns makes them a difficult target for field artillery to hit, in spite of the accuracy with which the latter can adjust its fire.

4. MACHINE GUNS IN GERMANY.

The German machine gun (drawn by 4 horses driven from the saddle) is mounted upon a sled which forms the firing frame. On the march, this sled is placed on a wheeled carriage, from which it must first be detached (10-15 seconds) before the gun is used; in exceptional cases, the gun can be fired from the wheeled carriage.

The gun commander is mounted. Two of the gunners are seated on the axle chest of the carriage, their carbines buckled to the gun carriage; two are seated on the limber chest, their carbines slung over their backs. When surprised by a direct attack, all the men that can be spared form as skirmishers in the intervals between the guns of the machine gun battery. The machine gun can be served by a single man. The water in the jacket need not necessarily be renewed when the gun is fired for a short time only.

The machine guns can be used on any terrain passable for infantry. When detached from the wheeled carriage they can even surmount considerable obstacles. In action, they present no larger target than skirmishers fighting under similar conditions, and are capable of offering more resistance than infantry.

The sled can be carried or drawn by the men for short distances. The ammunition, placed in belts holding 250 rounds each, and packed in six boxes, is similarly drawn on an ammunition sled. If the conditions permit, the guns may be drawn by horses.

The “fighting battery” consists of six guns, formed into three platoons, and an ammunition platoon (three ammunition wagons and one store wagon); the combat train consists of officers’ and other led horses. The field train consists of one baggage wagon, one ration (commissary) wagon, one forage wagon, and a second store wagon.

The movements and gaits of a machine gun battery are the same as those of a field battery: the order in line, at close or extended intervals, in which the guns are abreast, the intervals between them, measured from center to center, being 5 and 17 paces, respectively. The order in line, at extended intervals, is used in moving to the front or rear; the order in line, at close intervals, for assembly, for movements in that formation, for parking, and for parade. The section column[290] is the principal maneuver formation on the battlefield; it is employed as an assembly formation on a road, and as route column. (Par. 320 German F. S. R.). In section column the guns follow each other at a distance of four paces. In addition to this column, a column of platoons is used, in which the platoons follow each other at a distance of 22 paces. (This may be reduced to 6 paces).

A machine gun battery has available 87,300 rounds of ammunition (10,500 rounds with each gun and 8100 rounds in each ammunition wagon, or a total of 14,550 rounds per gun), which may be drawn forward to the firing position upon sleds, in boxes holding 250 rounds each. The ammunition wagons are refilled from the ammunition wagons of the light ammunition columns of the cavalry division and from the wagons of the infantry ammunition columns marked with a red stripe, which carry ammunition for machine gun units. A reserve machine gun is carried with the ammunition column.

The machine gun battery combines high infantry fire power (approximately equivalent to that of the skirmishers of a German cavalry regiment, armed with carbines, or to that of 4-6 platoons of infantry)[291] with instant readiness for firing, and a mobility which enables it to follow the mounted arms anywhere. The chance of producing a sudden fire effect within a short space of time must be especially utilized, and, therefore, an endeavor should be made to put entire machine gun batteries into the first line. The employment of single guns is precluded owing to the danger of breakdowns, and the employment of platoons is especially proper on the defensive as well as in action at short range.

The duties of machine guns naturally grow out of their tactical advantages. Their fire power should be saved for decisive moments, when the development of strong fire power at short ranges is requisite, and when the available time and the situation do not permit of pushing infantry into action. The machine gun batteries, which constitute an independent arm, and which are assigned to cavalry and infantry divisions, are best adapted for these duties.

The heavy matériel and the teams designed for rapid movements make the machine gun battery less suited for employment in infantry combat, where such a high degree of mobility is not so necessary. In the battle on the Shaho an employment of machine guns by platoons in the first line, came about quite naturally. The guns prepared the assault, reinforced weak points, and supported the advance. In Germany, provisional machine gun companies consisting of six two-horse machine guns, driven from the carriage (these guns cannot be fired from their carriages), have been adopted for this purpose. These machine gun companies are principally an auxiliary weapon of the infantry, and, distributed by platoons to the battalions, or sent into action as a single unit by the regimental commander, they serve the purpose of augmenting the fire of the infantry.

Movements at increased gaits are possible in exceptional cases only; as a rule, the guns follow the infantry at a walk, and in combats terminating in a defeat, it may frequently be impossible to keep them from falling into the hands of the enemy. The permanent assignment of machine guns to battalions does not seem to be advisable.

5. GOING INTO POSITION.

The principles which govern the reconnaissance and occupation of a position by field artillery are applicable also to machine guns. The tactical situation determines whether the guns should move into position under cover or in the open. As a rule, the interval between two adjacent machine guns in line is 17 paces; but the proper utilization of favorable cover does not preclude posting the guns close together. It may likewise be advantageous to post the guns in echelon on the flanks.

In action the carriages remain, as a rule, in the nearest cover in rear of the line. The advance from this point is effected by the men carrying or dragging the detached guns and ammunition sleds; under certain circumstances, it may also be advisable to have the guns or ammunition sleds drawn forward by single horses (mounts of gun commanders). On level ground the ammunition platoon and the wheeled carriages of the machine guns take post in rear of and as close as possible to the guns. Whether the two groups are combined, or whether the machine gun carriages should occupy the nearest, and the ammunition wagons the more distant cover, depends upon the available cover. The commander of the machine gun carriages sends full ammunition sleds to the firing line at an early moment and has empty boxes and belts brought back.

6. THE FIRE FIGHT.