Rifles_And_Light_Machine-Guns

"Rifles And Light Machine-Guns (see 23.325 and 17.237). - Since 1910 there have been few important changes in the design of the military bolt-action rifle. The adoption by many countries of the pointed bullet in lieu of the round-nosed (see 23.328) has led to some strengthening of parts so as to withstand increased chamber pressures. Modifications in the patterns of sights used have also been made here and there.' The military rifle had practically reached its zenith before 1914, and the opening of the World War found all armies equipped with rifles of practically equal merit. With the exception that the French continued to use the tube-magazine Lebel rifle and the British and Americans had adopted a shorter barrel than the rest, it might be said that the military rifles of the world were not only equal in merit but similar in design.

This initial equivalence of the opposed rifles continued throughout the war period. Further changes of detail were made. Special rifles were sometimes brought into use for snipers, and fittings were added to the standard service rifle to adapt it as a grenade-thrower and as a sniper's weapon to be used from a deep trench. A heavy single-loader was designed in Germany as an anti-tank weapon, and many changes were made in the ammunition. But the rifle itself, the rifle of the average infantryman, was practically the same at the end of the war as it had been for the past 15 years, or, setting aside the change of bullet type, for twenty-five. The German army of 1918 carried the 1898 rifle, the French the Lebel model 1886-93, the Italians the Mannlicher-Carcano of 1891. The Russian three-line (-3-in.) rifle of 1900 was only a modification of the earlier Moussin and Nagant models. The most modern patterns were the British and the American, and these were characterized by having a relatively short barrel, experience in the S. African War having brought " snap shooting " and the consequent need of handiness into relief. Otherwise the elements and their functions were the same, and the dimensions of the same order, in all rifles except the French.

This standstill of progress, in a time when the design of every other kind of weapon was developing at an unprecedented rate, is very remarkable and indicates clearly enough that the military rifle of the conventional type had reached its zenith. As a type, it was not capable of much further development. Designers had already by 1914 produced the first practical models of automatic and semi-automatic arms. Governments were unwilling to re-arm their troops and re-stock their armouries with new models of an obsolescent class. Even the French, whose rifle was not only the oldest but also possessed a type of magazine long discarded by others, made no attempt to replace it by a weapon of the class of the British and American rifles. When war came, all Powers were waiting on events.

In the war itself the machine-gun proper very soon and decisively asserted itself, driving the simple rifle into the back For further information see Ammunition and Sights.

ground. Further, trench warfare took unforeseen shapes. Grenades, trench mortars, bombs and man-to-man weapons, even clubs and daggers, became normal infantry arms in minor and subordinate combats, while in the battle proper it was the artillery and the machine-gun rather than the firing-line of rifle-armed infantry that governed the issue both in attack and in defence. Thus when, from the latter part of 1916 onwards, the " break-through," with its sequel of free infantry fighting in the background of the broken-through trench systems, became the ideal of tactics, the main infantry weapon was inevitably the machine-gun in some form. And thereupon the machine-gun of the pre-war and early war period began to develop on two distinct lines - the heavy machine-gun with its own role and characteristics (see Machine-Gun), and the light machine-gun or infantry machine-gun. When this evolution set in, the machine-rifle or automatic rifle (some forms of which were already in use as machine-guns, especially with aircraft) was more or less ready to take up the place allotted to it by tactics.

The light machine-gun or machine-rifle--" infantry machinegun " is a better designation than either for the class as a whole - is differentiated from the heavy machine-gun, technically and tactically, by being: (a) portable by one man; (b) unprovided with a mounting in the proper sense; (c) as inconspicuous in action or movement as an ordinary rifle; and (d) limited for various reasons to short bursts of fire. On the other side, as against the rifle, it possesses: (a) fire power with which no hand-operated weapon can compete, which indeed is equivalent for some moments at a time to that of the machine-gun proper; (b) an accuracy that, while less than that of the heavy type, is greater than that of the rifle, owing to the absence of trigger jerk and disturbance of the firer by recoil and to the fact that a muzzle support is (usually) provided; (c) ease and certainty in the matter of fire control, a mechanical organ in the hands of one man being far more manageable in the confusion of battle than a squad of extended riflemen. These advantages it gains, of course, at the expense of being more cumbrous, more delicate in mechanism and more expensive than the rifle, and it requires a fuller ammunition supply, or may do so. Further, it lacks one of the characteristics of the old infantry firearm - it cannot serve as the haft of a bayonet, and thus the infantryman ceases, at least for the time being, to be self-sufficing, and infantry organization at its lowest level returns to the 17th-century form, in which a fire element and a shock element are combined in the tactical group rather than in the individual soldier.

The characteristics of automatic rifle and light machine-gun fire, which thus become the most important element of infantry tactics, are briefly as follows. (For convenience, the term " automatic rifle " will be applied to the lighter and that of " light machine-gun " to the heavier members of the class under consideration. The definition by weight adopted in the following article fixes the frontier between the automatic rifle and the light machine-gun at about 20 lb.) The trajectory of an individual round, whether fired from a rifle, an automatic rifle, a light machine-gun or a heavy machinegun, is the same for the same ammunition and barrel characteristics, though its relation to the object aimed at will vary to some extent according to steadiness of man or mounting, smoothness or shock of recoil and other factors. On the other hand, the cone or sheaf of fire formed by a group of rounds will be denser with the automatic rifle and denser still with the light machine-gun than it is with a number of rifles representing the same volume of fire per unit time. The grouping of shots is densest of all in the case of the heavy machine-gun fired from a steady mounting.

In proportion, therefore, as the steadiness in position, due to man, ground or mounting, enables an automatic rifle or light machine-gun to group its shots more and more closely, these weapons tend to acquire more and more of the peculiar tactical powers of the heavy machine-gun - the ability: (a) to support close-fighting infantry groups by overhead or acute flanking fire; (b) to pour a direct and intense fire into small but dangerous posts of the enemy, such as machine-gun nests; (c) to enfilade enemy trenches and harass bridge approaches, cross-roads, and other points of very small area by day or night. It may be admitted at once that no existing light machine-gun and, a fortiori, no automatic rifle, is fully capable of (a) and (c), and in particular of overhead fire or fire through intervals between moving or fighting bodies of friendly troops without endangering them. However, in (b) the light machine-gun is ballistically scarcely inferior to the heavy machine-gun. This is its true function, which it performs as a rule better than the heavy, because its mobility allows of a closer approach, easier observation and freer choice of position. The automatic rifle also possesses this power in some measure, but the light weapon of the future to be evolved from the two types must, before unity of type is acceptable, be made quite as capable of performing this tactical service as is the light machine-gun of to-day. At present the automatic rifle seems to be looked upon in some quarters as a weapon to be used normally as a semi-automatic, firing perhaps 50 or 60 rounds where the bolt-action rifle would deliver 10 and to that extent economizing men, reducing confusion, and minimizing casualties in the firing line, but in the last analysis always a rifle in the tactical sense. Its automatic power is reserved for special emergencies, just as, at the beginning of the evolution of the magazine rifle, the magazine was regarded as a reserve of fire power added to a single-loader.

Considering, next, volume of fire, we can safely say that for practical purposes all automatic rifles and light machine-guns have or can be made to have the same rapidity of fire as the heavy machine-gun. The rapidity is purely a function of the design. Whether recoil-operated or gas-operated, the cycle of operations is gone through as fast as the mechanism can take up the motive impulse. On the other hand, the possibility of maintaining the automatic rate for long without damaging the mechanism depends on (a) the solidity of the working parts; and (b) the capacity of the barrel to resist overheating. In both respects the light machine-gun and the automatic rifle are definitely inferior to the heavy. Solidity of working parts and the incorporation in the design of cooling devices both involve deadweight, and it is the designer's first object to eliminate deadweight. In the automatic rifle not only are weights of parts limited but cooling devices are omitted altogether.' The possibility of automatic continuous fire is therefore definitely sacrificed. In light machine-guns, on the other hand, the working parts are not greatly different in solidity from those of heavy machineguns, and some form of cooling device - radiator, circulator or both - is invariably fitted. The extra weight translates itself into greater power of sustained fire. With a positive cooling system, such as the water-jacket of the German L.M.G.08/15, the volume of fire from a light machine-gun is practically equal to that of a heavy, if tactical conditions allow of equal ammunition supply to each. Even the air-cooled guns are capable of delivering many hundred rounds without a pause other than those for changing magazines or belts. It is true that the development of full fire power for several minutes continuously is exceptional and even very exceptional, and it is a matter of opinion how much importance should be attached to this factor relatively to others in the arm of the future. But it seems clear, in any event, that the infantry machine-gun which constitutes the backbone of the attack or the defence ought to possess, at least at the shorter ranges, that power of focussing a storm of bullets on the enemy's machine-gun group, nest, or other centre of effort as soon as it is located. Otherwise the attack or counterattack must wait for the heavy machine-guns to come well up, or at least to wait till exact information as to the target and the situation has been communicated to them.

This line of reasoning would exclude the automatic rifle altogether but for certain other considerations. The blotting-out by destruction or neutralization of well or strongly posted enemy groups in key positions is not the only function of the infantry machine-gun. It prepares by its fire every local advance of the groups of its own side, whether against or past important hostile nuclei or against simple parties of infantry using fortuitous 1 Except in the Chauchat, which is on the border line as to weight.

cover, which constitute the rest of the hostile " line." It is the latter which is the average, though not the decisive, incident in mobile warfare, especially when, as in 1918, the principle is to " drive a nail where it will go." In these average incidents sustained fire is the rare exception - German light machine-gun squads in the spring offensive of 1918, for instance, seem to have found that 2,000 rounds daily per L.M.G. sufficed - and mobility is of supreme importance as the machine-guns must push along as fast as the rest of the infantry, and, indeed, get ahead of it in many cases. This is a strong, and indeed the principal, argument in favour of the automatic rifle of less than 20 lb. weight., as against the light machine-gun of 20-40.

In sum, therefore, the light machine-gun, by reason of its greater weight and steadiness, can deliver a fire of greater accuracy and more sustained intensity than the automatic rifle, and so can perform functions for which the heavy machine-gun would otherwise have to be called in. The automatic rifle, on the other hand, possesses a greater mobility than does the light machine-gun and can for a few moments at a time develop a fire power practically as heavy. In four-fifths of a day's work in battl, then, it is as useful as, or more useful than, the light machine-gun. But the last fifth, often more important than the rest put together, it cannot undertake with much hope of success. Both have the disadvantage that they must be fed with ammunition in very difficult conditions. They must, therefore, be squad weapons and not personal weapons, and there is a tendency for the squad to group itself about the gun and so to reveal itself for what it is. Both, on the other hand, have the advantage that very few of these squads are needed, as compared with rifle-armed infantry, to attack or defend a given front.

On the whole, it seems probable that a type of the future, evolved from both, will take the form, not of the lightened machine-gun, but of the automatic rifle provided with increased magazine capacity, a cooling device, and a mount sufficiently steady, with the weight of the gun, to give a bullet grouping at short ranges as close as that of the heavy machine-gun at longer.

The rise of the light machine-gun to importance as the main weapon of the infantry battle has been followed by another development of some interest, viz. a change of principle in what may be called the personal armament of the infantry soldier. Hitherto self-sufficing, but now become a member of a gun detachment, he has felt the need of possessing some handy weapon of his own which would give him intense fire power in emergencies. The same is the case with the artilleryman and, in the present day, with many specialists such as range-takers, observers and others, who have to work in the front line but are not armed with the normal battle weapon. For these, first an increase in the capacity of the pistol magazine was tried, and later an altogether new class of weapon was designed - the machine-pistol, which is a fully automatic arm of the carbine or long pistol kind, capable of firing pistol ammunition as fast as a heavy machine-gun fires rifle calibre ammunition. Such weapons may also usefully replace the light machine-gun itself in certain conditions, e.g. bush or mountain warfare. Some examples of this new class of arm are described below.

As to whether the semi-automatic rifle - that is, the military rifle fitted with self-loading mechanism but fired by the trigger shot for shot - will become a universal infantry weapon, opinions differ. On the whole, it seems unlikely that it will do so. On the one hand, for group action the light machine-gun or perfected automatic rifle is definitely superior in accuracy, volume, and control of fire to an equivalent number of semi-automatic rifles in individual hands, whatever the discipline and team work of the individuals. On the other hand, as a personal armament for fighting at close quarters the new machine-pistol is superior in intensity of fire and at least equal in handiness. The semi-automatic rifle may develop as a weapon for sniping and skirmishing, and as the soldier's personal armament in theatres of war where the country is very open and troops are required to do a good deal of individual patrolling and stalking. Of these services, however, all except sniping can be performed by the machine-pistol; and, in sum, the semi-automatic rifle seems likely as a military arm to become a sniper's rifle pure and simple - the military analogue of the sporting rifle, for which the semi-automatic principle is already well established. Speculation as to the nature of the cavalry firearm of the future is now difficult, depending as it does on the tactical question of how far dispersion will be carried in the dismounted fire fight. (C. F. A.) Practical Developments The improvement of the rifle has been confined mainly to the development of auto-loading, or semi-automatic, rifles for both military and sporting purposes, and the development of the automatic or machine-rifle for military purposes.

The semi-automatic shoulder-rifle has become an efficient and reliable weapon for sporting purposes, but no military weapon of this type has been adopted by any of the leading powers to replace the bolt-action shoulder-rifle, although some fairly successful weapons have been produced. The principal difficulty in the way of perfection of an arm of this type is the weight limitation. The present bolt-action rifles are considered by many designers to be as light as is consistent with the pressures obtained with modern powders, and the automatic action can only be obtained through additional parts, and consequently additional weight. Successful automatic rifles of 12-20 lb. weight have indeed been produced. Such rifles are somewhat less heavy than the light machine-gun, the latter being defined as an automatic, rifle-calibre weapon, with a tripod as muzzle support weighing from 20 to 30 lb. complete, and it is possible that further developments in the type may lead to its superseding the light machine-gun as above defined.

## Bolt-Action Military Rifles

It has already been noted that no important progress was made in the design of the bolt-action rifle during the World War. Quite apart from the manufacturing difficulties attending upon an alteration of model in the midst of a great crisis, and setting aside also the changes in the tactical relations of rifle, gun and machine-gun in the war, the rifles used by the various belligerents were so nearly equivalent that no one possessed any advantage over the rest which could not be compensated for by slightly better training or slightly higher moral on the other side. And not only was the invention of necessity wanting, but also the conventional type of rifle had reached a point of development beyond which it was difficult to see possibilities of radical improvement.

Substantially, then, the rifles in use at the end of the war were the same as those in use at its beginning, and this is the less surprising as many peace-time criticisms levelled at one or another model proved to be useless, or practically unimportant, in war. Thus, rifles looked upon as obsolete revealed unsuspected good qualities in the severe test of war service, and modern rifles failed to show the superiority expected. The German Mauser had been popularly credited with being the best military shoulder arm; while the British short Lee-Enfield had been severely criticized on the score of its weak body and poorly designed bolt. Yet, under service conditions, the performance of the latter was excellent; the simple action, good balance, and rapidity with which it could be worked compensating for the superior ballistic qualities of the German arm. Similarly, the French Lebel, one of the oldest service rifles (1886-93), has been looked upon as being outclassed by modern arms, it being the only military rifle with a tubular magazine; yet this rifle with the " Balle D " cartridge has greater velocity and greater striking power at ranges in excess of 800 yd. than the American Springfield, which has 360 f.s. greater initial velocity. In only one instance, apparently, did a rifle prove so unsuitable that it was withdrawn from use. The Ross rifle, the original arm of the Canadian forces, while a good sporting and target rifle, proved unsatisfactory in the mud and dirt of trench fighting.

Another factor which tended to stabilize the rifle in its existing form was the interchangeability of rifle and machine-gun ammunition. Before the war there was a distinct tendency towards reducing the calibre of the rifle and employing a lighter bullet, in order to obtain flatness of trajectory at ranges within about 800 yards. But the modern light-weight high-velocity bullet loses its velocity very rapidly, which renders it less suitable than a heavier bullet for employment in machine-gun work, where effectiveness at long range is required. So long, therefore, as the ammunition of rifles and machine-guns remains interchangeable it is probable that no further reductions of calibre and bullet weight will take place. At the same time, the development of the heavy machine-gun itself may quite possibly call for not merely the retention of the present common calibre but an actual increase of calibre beyond what is admissible for the rifle. The principle of interchangeable aiixniunition has recently been questioned by some experts who would prefer that each class of weapon should be free to develop along its own lines; and already experiments have been carried out in the United States, not indeed with two calibre, but with two bullet weights, a bullet of 180 grains being designed for the machine-gun (and for occasional use for special purposes in the rifle) while the old bullet of i 50 grains is retained for the shoulder weapon.

The only new model service bolt-action rifle produced by belligerents during the war on a large scale was the British rifle, 303, pattern 1914, which was later adapted to 30 U.S. ammunition and manufactured for the United States; about 2,50o,000 rifles of this type being produced in that country during the eighteen months preceding the Armistice.

British Rifles of the War Period. - Before the war, the British service rifle, the short Lee-Enfield of 303-in. calibre, had been subjected to a good deal of criticism, and the War Office, after much experimenting with various types of cartridges, found that it was not possible to obtain as high a velocity with this rifle as was desired. An improvement was effected, however, in the adoption of the Mark VII. ammunition, the pointed bullet of which weighs 174 grains instead of 255 grains as in the Mark VI., the muzzle velocity being 2,440 f.s., with a chamber pressure of 45, 0 0 0 lb. This ammunition, however, did not give the ballistic qualities desired and the design of a new rifle was taken up. A rifle was finally evolved with a bore 276 in. in diameter, and chambered for a rimless cartridge, giving a muzzle velocity of about 2,800 f.s., and a chamber pressure of 51,000 lb., and it is probable that this model would have been further perfected and adopted but for the beginning of the war. Military considerations then prevented its adoption in its original form, and it was modified to take the existing Mark VII. 303 ammunition, and manufactured in the United States as the " British Rifle, Pattern 1914." The short magazine Lee-Enfield with Mark VII. ammunition, however, remained the standard British arm throughout the war; though the new rifle was also used.

Upon the entrance of the United States into the conflict, as a number of American factories were equipped to manufacture this rifle, it was again modified to accommodate the U.S. service ammunition and used as a substitute for the calibre 30, model of 1903 (Springfield), under the name of the " U.S. Rifle Model of 1917." As chambered and bored for the U.S. ammunition, the rifle had approximately the same ballistic qualities as the Springfield. The British and American models of this rifle are the same in their essential features, except that the latter has not the long-range (dial and aperture) sights of British rifles. A remarkable feature common to both rifles is the position of the rear sight between two protecting lugs on the bridge of the receiver. This position of the rear sight gives a distance from back sight and fore sight of 31.76 in., that is, almost exactly over the trigger instead of in the customary position, a hand's breadth or more in front of the magazine. Further details will be found in the article Sights. The length of the rifle overall is 46.3 inches. The weight without bayonet is 9 lb., 3 oz.; the sword bayonet is about 22 in. long (blade 17 in.) and weighs 15 oz. The magazine holds five cartridges which are loaded from a clip. The bore has five grooves, left-hand uniform twist, one turn in io inches.

The action of this rifle is as follows (figs. I and 2). The cycle of operations is assumed to start with the extraction of a fired cartridge case. The bolt handle is raised and the cocking piece forced to the rear in the bolt by the half-cocking cam. This also withdraws the striker into the bolt. When the locking lugs on the bolt are clear the extracting cams on the bolt and receiver engage and the continued rotation of the bolt retracts the latter and loosens and partly withdraws the cartridge case (primary extraction), the extractor and sleeve being prevented from turning by the receiver. When the limit of the turning movement in the bolt is reached, it is drawn to the rear, withdrawing the empty cartridge case; during this movement the cocking piece rides over the sear nose and depresses it; the safety stud rises in the clearance cut in the bolt. When the cocking piece clears the sear nose, the sear spring returns the sear to normal position. The slotted locking lug (left hand) of the bolt now reaches the ejector, the latter proti'uding in the slot sufficiently to strike the rear of the empty case and eject it to the right. After a further slight backward movement the bolt lug comes in contact with the bolt stop, preventing further movement. If the magazine is now empty the follower rises and its rib prevents the closing of the bolt. If not, the magazine spring has pushed another cartridge up and into the path of the bolt, the forward movement of which forces it forward and up over the cartridge ramp.

During the early part of the closing movement of the bolt, the ejector is pushed outward by the bolt. Later, the sear notch in the cocking piece engages the sear nose, and is arrested. The bolt then slides forward over the striker, further compressing the main spring.

When the rotation of the bolt by the handle begins, the locking lugs engage the locking cams, and force the bolt home, seating the cartridge, and further compressing the main spring. The rotation of the bolt restores the half cocking cam, so that it is out of the path of fall of the cocking-piece lug.

The bolt is now locked, the mainspring is fully compressed, and the cocking piece is held by the sear nose.

When the trigger is squeezed, the bearing of the trigger first acts on the bearing of the receiver, slowly depressing the sear nose. Then the heel of the trigger engages the receiver, and completes the depression of the sear nose, which ends in the release of the cocking piece by the sear nose. The striker is then acted upon by the mainspring, and, striking the primer of the cartridge, detonates the same.

FIGS. I and 2. - British Rifle (Pattern '14) U.S. Model of 1917.

During the depression of the sear nose, the safety stud rises through the hole in the bottom of the well and enters the interlock slot in the bolt. If the bolt is not fully locked, the interlock slot will not register with the safety stud, and the trigger cannot be pulled.

## United States

When the United States entered the war its standard rifle was the " U.S. Rifle, Model of 1903 " (Springfield). There were only about 600,000 of these on hand, and very limited possibilities of immediate expansion. To obviate delay, therefore, it was decided, as above mentioned, to adopt the British Pattern '14 rifle which had been manufactured in the United States in large quantities. This rifle, modified as previously noted, was used very successfully by a large portion of the U.S. troops; only the regular army and part of the National Guard continuing to use the Springfield. The Springfield, however, is still (1921) the official arm, the 1917 rifles having been withdrawn after the Armistice.

## Other Nations

The Lebel magazine rifle, calibre 8 mm., model of 1886-93, is still the standard arm of the French infantry. The magazine is tubular, lies under the barrel, and holds eight cartridges which are loaded singly. The carbine, model of 1890,. and the rifle, model of 1907-15, were also used to a considerable extent. These are magazine rifles, having a one-piece stock and a bolt with a turning head. They are loaded with a charger containing three cartridges. A box magazine was later designed for these rifles, increasing the capacity to five cartridges. Several other types were used by the French, many of the old singleloading " Gras " rifles of the 1874 model being adapted.' Mauser rifles in different calibres were used by Germany, Turkey, China, Portugal, Serbia and Brazil.' The Japanese " Arisaka," or "38th Year," also has a Mauser action. Many of these rifles were purchased from Japan by Russia early in the World War and also by Great Britain for training purposes. It was reported that since the Armistice Japan has increased the calibre both in new rifles and in the existing stock from 6.5 mm. (256) to 7 mm., the reason given for the change being that the 6.5-mm. bullet is too small to develop sufficient wounding power. This calibre is used by several other nations and is the smallest used in military rifles. The change is interesting, since the tendency had been towards reduction of calibre.

The standard arm of the Russian infantry is the " Three line " magazine rifle, 7.62-mm. (. 3-in.) calibre. A new type of ammunition has been adopted for this rifle, having a pointed bullet weighing 148 grains and giving 2,820 f.s. velocity with 50,000 lb. pressure. The Russian Government also bought large quantities of Winchester, model of 1895, magazine rifles of the same calibre, the only lever-action magazine-rifle used in the war.

Austria-Hungary used the 8-mm. Mannlicher, " Straight Pull " rifle, model 1895, and carbine. Mannlicher type rifles were also used by Italy, Bulgaria, Rumania and Greece. The Belgians used the magazine rifle, calibre 7.65 mm., model of 1889, which has a Mauser action. The latest ammunition for this rifle has a pointed bullet weighing 154 grains with a velocity of about 2,740 f.s. The Swiss Schmidt-Rubin rifle has been redesigned to chamber a new rimless cartridge having a 170grain streamline bullet with a velocity of 2,660 f.s.

Special Bolt-Action Rifles Snipers' Rifles. - Several types of rifles have been developed by the various Powers for the use of " snipers," whose function it is to pick off with single shots individual scouts, officers, men of working parties, enemy snipers, etc. Snipers work as a rule in pairs wherever feasible, one acting as an observer, the other as a rifleman. The rifle used for this purpose is usually a very carefully selected specimen of the standard service rifle, fitted with telescopic sights of low power, or some other variety of optical sights, though plain sights are sometimes used. The British snipers used the short Lee-Enfield rifle with various forms of telescopic and other optical sights, and also the 1914 rifle with a special back sight. The U. S. rifle is fitted with a Warner and Swasey telescopic sight, 6-power, 4-1. ° field, which is attached to the standard rifle by side brackets, but this combination is not entirely satisfactory and a new telescope and method of mounting are being developed. The German sniper's rifle was the standard Mauser with brackets fastened by screws to the top of the magazine to take a Goerz, Luxor, or Zeiss telescope, generally of 21 or 3 power. The mounting of the telescope over the bolt and magazine makes it necessary to use the rifle as a single-loader and prevents the use of the regular sights while the telescope is attached. This method is, however, preferred by riflemen as aim may be taken with the cheek against the stock in the usual manner; the superior accuracy obtained offsetting these disadvantages. In the German sniper's rifle the telescope can be very quickly removed from its brackets and the rifle used the ordinary way.

1 The German infantry throughout the war carried the 1898 pattern Mauser (7.9 mm.). The cavalry carbine of the same pattern and calibre was also occasionally used by infantry as well as by cavalry serving dismounted in the trenches, and by the personnel of light machine-gun squads. During the trench-warfare period of the war, spare magazines holding 25 cartridges were designed for attachment to the underside of the ordinary magazine, in order to obtain an increased volume of fire for emergencies; these were, however, clumsy and unpopular with the troops, and were not generally used. The only important modification of the standard arm was the introduction in summer 1915 of a short rifle (43'5 in.) known as the Erfurt rifle. This has the same trench action, calibre, and magazine as the 1888 rifle, and, apart from the reduced length, differs from it only in having the sliding parts of the breech covered by a dustproof metal casing, the barrel cased in wood (as in the British and other short rifles) and the muzzle filled with a flash-reducing attachment. The bolt-handle is curved down close to the stock. This weapon was only issued for service in the last months of the war, but seems to have been retained as a standard weapon in the post-war army and police. Troops of older categories employed in garrison and line of communication duties had the old magazine rifle of 1888 (7.9-mm. calibre).

2 The new Brazilian 7-mm. ammunition has the highest muzzlevelocity of any military small-arms ammunition, although several of the new cartridges closely approach it.

Periscopic Rifle Holders or " Sniperscopes " have been designed and used with some success, although it cannot be said that these devices were ever popular or capable of very accurate or rapid fire. The tendency when using them is to shoot high and they are only reasonably accurate at ranges up to 200 yards. In the instrument developed by the Munition Invention Department of the British Government (fig. 3) the periscope (aa) and shoulder piece (c) are rigidly combined with each other and with a shoe (d) which takes the butt of the rifle. A trigger on the shoulder piece is connected to the rifle trigger by a cord (eee). Pivoted to the right side of the shoe is a system of levers (bbb) which enables the firer to open and close the bolt by means of a handle close to his right hand. The periscope itself is a simple mirror-periscope.

FIG. 3. - Periscopic Rifle Holder (British Type).

Anti-tank Rifle. - The German anti-tank rifle (fig. 4) is a singleshot calibre 13-mm. Mauser action rifle brought out as an emergency weapon a and intended to serve as a stop-gap pending the construction of a 13-mm. machine-gun. The weapon is intended for shortrange work only, as the sights are graduated to only 500 metres. It is very heavy (37 lb.) and has a total length of nearly 66 in., the barrel being 39 in. long. It is provided with a bipod. The bullet, which weighs 801 grains, is pointed and armour-piercing, has an initial velocity of about 2,450 f.s., and a penetration of 20 millimetres in the best steel is claimed at a range of 500 yards. It is, however, very heavy for a portable arm, and, being a single-shot weapon, it has a very slow rate of fire. On account of the heating of the barrel and the heavy recoil, the fire cannot be sustained for more than 20 shots at a time. Each rifle was served by two men, carrying 124 cartridges as well as the rifle and accessories and their personal armament. The rifles were used in squads of three rifles, or singly, or in cooperation with heavy machine-guns using armour-piercing bullets, according to circumstances. The Germans had a high regard for this weapon.

FIG. 4. - German Anti-Tank Rifle.

High-power Rifles. - Sporting rifles with an initial velocity of 3,000 f.s., or slightly more, are now in use. These rifles have no particular feature except the additional strength necessary to withstand high pressures. The so-called " explosive " effect of high-velocity bullets upon striking make them extremely effective for sporting purposes.

Semi-Automatic Rifles As already mentioned, efforts are being made to produce a semiautomatic shoulder-rifle to replace the bolt-action rifle. The successful sporting weapons of this type which have been devised are not considered suitable for military use, as the powder pressures and velocities obtained from their cartridges are much below those obtained with military ammunition. Sporting rifles are not subjected to the severe conditions that are usually encountered by the military The order for a design was given in Dec. 1917 and in spite of the manufacturing difficulties which naturally presented themselves with an arm of such unusual proportions, the Mauser works were able to begin quantity supply in April 1918 (Schwarte, Technik im Weltkriege, p. 21). (C. F. A.) arm; the sportsman seldom fires more than three or four shots in quick succession and is usually in a position to give the self-loading rifle the care which its more complicated mechanism requires.

The principal requirements in a semi-automatic rifle are that the rifle shall not weigh more than nine or ten pounds, and shall have a simple mechanism which will stand the shock of service ammunition and the wear and tear of campaigning. The weapon must be capable of being used either automatically or by hand as an ordinary rifle, and for the rest must possess all the qualities now demanded of a good bolt-action rifle. The automatic action, therefore, is not considered a substitute for any of the qualities of the present shoulder-rifle. No semi-automatic weapon so far designed has fulfilled these conditions to such a degree that it has been adopted in place of the bolt-action rifle. The Mondragon, a Mexican invention, has, however, been used by the Mexican Government to some extent, and in a modified form. A modification of this weapon was also used by Germany in the war, notably for the armament of aeroplanes. Two French models, the St. Etienne and the " Carabine Meunier," were brought out toward the close of the war, but not extensively used.

FIG. 5. - Winchester Auto-Loading Rifle.

The U.S. Ordnance Department recentl y (1920) held competitive tests, and further developments and tests have been made. The principal advantages expected from the semi-automatic rifles are: increased rapidity of fire, less physical labour on the part of the soldier, and better moral, due to the knowledge that he can devote all his attention to the enemy and shoot without exertion or haste when necessary. On the other hand, the desirability of the semi-automatic rifle is not universally conceded. Some authorities consider the rate of fire of the present rifle to be quite as high as is consistent with accurate shooting and lay stress on the difficulties of ammunition supply.' Semi-automatic Sporting Rifles. - The Winchester auto-loading system for rifles (fig. 5) utilizes the inertia of a heavily weighted bolt working against the compression of a coiled spring in the fore end to delay the rearward motion of the bolt at the moment of firing until the bullet has left the barrel. After this inertia is overcome, there still remains enough force to the recoil to move the bolt to the rear, eject the empty cartridge case, cock the hammer against the compression of the hammer spring, and finish the compression of the bolt FIG. 6. - Browning Auto-Loading Rifle.

sprung. When this has been accomplished, the bolt moves forward actuated by the bolt spring and feeds another cartridge into the chamber. A pull of the trigger now fires another shot. This rifle is made in various calibres, the most powerful being. 401 in. The 200grain bullet in this size gives a muzzle-velocity of 2,132 f.s. and has a muzzle-energy of 2,020 foot pounds. The French Air Service used this type of rifle to a limited extent in the armament of aeroplanes.

The Browning auto-loading system (fig. 6), used by Remington (U.S.A.) and the Fabrique Nationale (Belgium), differs from the Winchester in that the barrel (1), breech bolt (2), and bolt carrier (3) are locked together at the moment of firing, these parts recoiling together against a powerful spring (7) in a casing surrounding the barrel and in which the barrel slides. The rearward motion pushes the hammer (¢) backward, cocking the action and compressing the ' The incorporation of the light machine-gun in the small fighting unit of infantry bears on this question. (C. F. A.) action spring (5) through the link (6) and the recoil spring (7).

A buffer spring (8) also serves to retard the recoiling parts. At the completion of the backward motion the bolt-carrier latch (9) springs into a notch (to), locking the bolt in its rearmost position. The barrel and bolt carrier now start forward actuated by the recoil spring around the barrel; the bolt carrier after moving a short distance is held by the bolt-carrier latch; the barrel continues its forward movement, turning the bolt by means of a helical cam slot in its side and unlocking it. The empty cartridge case is held until the forward motion of the barrel withdraws it from the chamber, after which it is ejected. When the barrel has reached its forward position, the barrel extension (11) has forced the barrel lock down. This reacts against the bolt-carrier latch and allows the bolt carrier to be pushed forward by the action spring (5), carrying a fresh cartridge from the magazine (12) into the chamber and rotating the bolt so that the locking lugs are forced into their seats in the barrel extension, thus locking the bolt to the barrel.

6 5 FIG. 7. - Mondragon Semi-Auto Rifle.

This rifle is made in 25-in., 30-in., 32-in., and 35-in. calibres. In the last-named the 200-grain bullet has a muzzle-velocity of 2,020 f.s. and an energy of 1,776 lb. The magazine is loaded with a clip of five cartridges similar to military rifles. Owing to the locked bolt and recoiling barrel, high pressures can be used in this arm. The cartridge is reduced in diameter or necked down for the bullet. The mechanism is, however, much more complicated than in a rifle where the breech only is blown back.

## Semi-automatic Military Rifles

The Mondragon semi-automatic military rifle (fig. 7) is the invention of Gen. Mondragon of the Mexican army. It was invented about 1891 and developed to its present state by Germany about 1915. The rifle is gas-operated, the gas being taken from a port in the barrel. It weighs about nine pounds, has the general appearance of the ordinary service rifle, is fitted for a bayonet, and is made in 7-mm. calibre. The characteristic feature of this rifle is the bolt mechanism, which permits the rifle to be used either as an auto-loading weapon or as a hand-operated shoulder rifle. The bolt (I) has three locking lugs on the forward end of the bolt and four on the rear end of the bolt, which are locked into locking recesses of the receiver (2). The bolt is made to rotate by two helical cam slots (3) in the side; two cam lugs, which are carried by the bolt handle, work these slots. The bolt handle is connected with the gas piston so that when the powder gases enter the gas chamber and drive the piston to the rear, the bolt handle is carried with it and causes the bolt to rotate and unlock, and move to the rear, extracts the empty case and compresses the recoil spring (4) which is coiled round the gas cylinder, and drives the mechanism forward after it has been arrested in the rear by the buffer spring. A gas adjustment is provided to regulate the amount of gas delivered to the gas cylinder, so that the rate of working can be to some extent regulated. The magazine has a capacity of 10 rounds. Another form of magazine, for aircraft purposes, is of the Luger "snail," or barrel type (see Pistol), and holds 30 rounds. The rifle is provided with a separate hammer (5) which is linked up with the trigger mechanism as FIG. 8. - St. Etienne Semi-Auto Rifle.

shown in the section. The change to hand-loading is done by means of a releasing catch on the bolt handle which disconnects this from the gas piston. The gas port in the barrel may also be closed by means of a valve. A safety device (6) is provided which disconnects the trigger if carried in a safe position.

The German pattern was officially known as the Aviator's Automatic Carbine (Flieger-Selbstlader Karabiner), model 1915, and was chiefly and successfully used for the purpose indicated by its name. It was also for a time tried as an artillery carbine, but for this purpose it proved unsuitable, in that it failed to stand the rough usage and careless handling of field warfare.

The St. Etienne Semi-automatic Rifle (a French " semi-automatic rifle,.model 1918 ") is a gas-operated semi-automatic rifle which weighs about 112 lb., is about 52 in. long, and has an ordinary rifle sight and bayonet fitting (fig.8). It takes the French Lebel 8-mm. cartridge. The magazine which has a capacity of five cartridges is charged through the bottom of the magazine housing (8), which is hinged.

When the bolt handle, which is attached to the bolt (9), is pulled to the rear, the hammer (io) is forced to the rear against the action of the hammer and sear spring (ii) until the sear (12) is engaged in the sear notch in the trigger (13). "I'he rearward motion of the bolt compresses the recoil spring (15) which, when the bolt handle is released at the rear position goes forward and drives the next cartridge into the chamber, while the hammer is held in the rear position by the sear and trigger ready for firing. The trigger is pulled and released for each shot, but extraction and ejection of the fired cartridge case and the feeding of the new cartridge are automatic. When the trigger is pulled, the sear is released and allows the hammer to go forward and strike the firing pin which ignites the cartridge. When the cartridge is ignited a portion of the powder gases pass through the gas port (16) into the gas cylinder (17) which drives the gas piston to the rear. The gas piston is linked with the bolt mechanism through a slide which transmits the force of the gases to the bolt. This serves to unlock the bolt and drive it to the rear to extract and eject the empty case and to compress the action spring and cock the hammer for the next shot. The bolt body is forced to the rear by the slide which is attached to the gas piston, and also linked with the bolt head (18) through rotating cams which rotate' the bolt head sufficiently to clear the bolt head locking lugs of the locking recesses in the receiver.

Automatic Rifles And Light Machine-Guns As has been stated in an earlier part of this article the development of new tactical methods and conditions in the World War soon produced a demand for a light machine-gun or automatic rifle which could keep up with, and participate in, an FIG. 9. - Browning Automatic Rifle.

infantry attack at every stage of its progress. Various types of weapons were adopted for this purpose and classified as light machine-guns or automatic rifles. There is no distinct separation of these types, the term " light machine-gun " being usually applied to machine-guns weighing 20 to 30 lb. fired from a bipod and used for fairly sustained direct fire. Practically all types are air-cooled by means of a heavy barrel with annular rings or a radiator. The automatic rifle, while it is sometimes supplied with a bipod, may be fired from the hip or shoulder and The rifle is light and portable, weighing only 152 lb. and being only an inch or two longer than the short military rifle. It can be handled by one man as a shoulder rifle. As it is heavier than the ordinary military rifle, the recoil is very slight, and a man can fire the gun continuously without distress.

By means of a change lever, the action of the gun is made either semi-automatic (the trigger being pulled for each shot), or automatic (being continuous as long as the trigger is kept pressed and cartridges are supplied).

As a semi-automatic rifle it is very effective. As the trigger pull is as light as that of an ordinary military rifle, it is possible with practice, to fire ioo shots a minute without unduly tiring the finger. Used in this manner every shot can be well directed, which makes the gun in some conditions as effective as the heavy machine-gun, with a considerable saving in the amount of ammunition expended.

The gun, firing automatically, has a rate of between 450 and 500 shots per minute. The speed can be regulated to a certain extent by adjustment of the gas regulator. The weapon can be used as freely when firing automatically as when firing single shots, the firer lying down, standing, or advancing at will.

When a magazine has been emptied it can be dropped out of the gun by pressing the magazine release in the trigger guard and a full magazine quickly pushed into place with one hand, so that very little time is lost in changing magazines.2 The mechanism is very simple and also extremely durable. Tests have been made where over 50,000 rounds have been fired out of the same rifle without any of the parts showing distress.

The rifle is gas-operated. A portion of the powder gases, while under pressure, are trapped near the muzzle of the gun and are caused to act upon a gas piston. The pressure of the gases forces the piston and slide to the rear against the action of the recoil spring, until stopped by the buffer, when the recoil spring returns the mechanism to its forward position.

The receiver (21) in which the barrel is firmly screwed contains the principal mechanism of the gun. The bolt-supports (23), upon which the bolt slides, are riveted in position. The bolt guide (25) fits in a slot cut in the receiver wall and is held in position by the bolt guide spring. The change lever stop (26) projects from a hole in the receiver wall in the path of the change lever and must be depressed before the change lever can be moved to the safe position. The buffer tube (28) behind the receiver contains an arrangement of friction cones, cups and springs. On the left-hand side of the receiver 44 28 23 l „,,,, ' ??

tCt. c"Z?la i ??!Iii. ? ' ..?  Fs /ii ' 'thl?/1[}??? ?II`??? ' 'j .T?? ??????e . ,? - ar??i? ', 1 rl i I_?Iir Fie:. io.--Browning Automatic Rifle.

is capable of delivering limited sustained fire. Its weight varies from 14 to 20 pounds. The German " 08/15 " and " 08/18 " and the Bergmann, Lewis and Benet-Mercie are generally spoken of as light machine-guns. The Browning, Chauchat, light Hotchkiss and Madsen are examples of automatic rifles.

The Browning Automatic Rifle (figs. 9 and to) is the standard automatic rifle of the United States army.' 1 Brought out in 1917, just after America entered the war, and available in small numbers by Feb. 1918, it was not employed in battle till Sept., Gen. Pershing having become so convinced of its superiority over all other types in use that he preferred not to expose it to capture and copying by the enemy till the American army had been supplied with it on a large scale and had reaped the fruits of its superiority in a great battle. In effect, none was used before his offensive battles of Sept. but 4,608 were in action between that date and the Armistice. (C. F. A.) are grooves in which the operating handle (34) slides. The forward end of the gas cylinder tube (36) is rigidly connected with the barrel. The bolt (39) carries the extractor (40) which is held by the extractor spring (41). The firing pin (42) fits in the bolt, and has a cam lug which engages with a corresponding cam surface on the bolt lock (43)The downward motion of the bolt lock forces the firing pin back and prevents it from touching the cap of the cartridge until the arm is ready to fire. The bolt lock and link (44) are pivoted to the rear end of the bolt. The link connects the bolt lock and the slide (45), which moves horizontally in grooves in the receiver, the gas piston (46) being permanently attached to it. The slide is slotted to permit the magazine to pass through it, and has a notch on its lower rear end to engage with the sear (47). The link pin (48) passes through the link, hammer (49), and slide, pinning the three parts 2 Magazines holding 20 cartridges are the standard size; they are also made to hold 30 and 40 cartridges. They are themselves filled by a device which presses in the cartridges, five at a time, from the usual clips.

together in such a manner that the link may swing on the pin as a pivot. The link pin also protrudes through a slot in the receiver to engage the operating handle. The recoil spring (55) is encased in the gas piston, its front end pushing forward on the piston while its rear end rests against the head of the recoil spring guide.

The sear (47) is pivoted in the sear carrier (51) by the sear pin which also holds the sear carrier to the trigger guard (52). The holes through which the sear pin passes in the trigger guard are slotted, allowing a slight horizontal movement of the sear carrier. When the sear engages in the notch of the moving slide, the counter recoil spring (53) acts as a buffer, allowing the sear carrier and sear to move instead of suddenly stopping the movement of the slide.

The ejector (54) is a flat spring which yields slightly when struck by the empty cartridge case so that the latter is gradually ejected.

## Action of the Mechanism

With the gun in the ready-to-feed position and the change lever set for semi-automatic fire the cycle of operation when the trigger is pulled is as follows: - The connector which is pivoted in the trigger moves the sear (47) out of engagement with the notch in the slide and is cammed forward allowing the sear to spring into position to engage the slide on its return. The recoil spring (55) which has been compressed during the recoil of the mechanism, drives the piston (46) and slide (45), carrying the bolt (39), bolt lock (43), link (44) and hammer (49) forward. As they move forward the lower edge of the bolt strikes the upper edge of the top cartridge in the magazine and drives it forward into the chamber.

As the parts are nearing their forward position, the rear of the bolt lock (43) which curves downward, comes in contact with the rounded end of the bolt-supports (23) and the rear end of the bolt lock is started moving upward. As the slide moves further forward, the top end of the link, which is pivoted to the bolt lock, tends to move upwards as the lower end is swung forward with the slide, and the link forces the rear end of the bolt lock in front of the recoil shoulder in the receiver, thus positively locking the breech, as shown in the illustration. The motion of the bolt as the bolt lock swings upward, is gradually stopped so that the bolt is not stopped suddenly, but very gently as its forward horizontal motion is transformed into the vertical motion of the rear of the bolt lock.

The hammer strikes the firing pin and the cartridge is ignited. The forward shoulders of the slide then strike the heavy buttment of the gas-cylinder tube, and the motion is arrested.

After the bullet passes the gas port in the barrel near its muzzle, the expanding gases enter the gas cylinder and drive the piston and slide rearward. The rear of the bolt lock is brought down away from the recoil shoulder of the receiver, and is started back, gradually starting the bolt rearward with it, but by the time the bolt starts to move, the pressure of the gases has subsided, so that the empty cartridge is no longer expanded against the walls of the chamber, but comes out freely. Extraction troubles are thus avoided. The bolt is both stopped and started gradually and is not damaged with hammerlike blows. The empty case is drawn from the chamber by the extractor until its under edge strikes the ejector, when it is ejected to the right and forward; this avoids interference with a man immediately to the gunner's right.

The recoiling parts are arrested when the slide strikes the buffer, and the sear once more engages in the sear notch, which holds the slide and bolt mechanism to the rear with the breech open.

69 by an aluminum radiator with annular corrugations surrounding the barrel. The backward and forward motion of the barrel causes air to be driven into the holes in the radiator casing (cf. the Lewis gun, fig. 14) which also assists in the cooling. The locking of the bolt mechanism is positive and is done by two locking lugs on the bolt head which are rotated into locking recesses of the breech casing. Lugs are provided to guide the bolt head and bring it in contact with the cam cuts in the bolt body. The cartridges are fed from a semicircular magazine holding 20 cartridges, when rim cartridges are used, and from a straight magazine when rimless cartridges are used. A regulator is provided, which adjusts the gun for safety, for automatic fire, or for semi-automatic fire.

The action of the mechanism is divided into two phases: the forward motion and the backward motion. The rifle is loaded by pulling the operating handle to the rear until the mechanism is arrested by the sear (J7). A charged magazine is inserted into the magazine opening in the gun, the magazine being held in place by the magazine catch (58). When the trigger is pulled it causes the trigger bar (59) to rotate the hand sear (60) against the under side of the breech casing (61). This forces the sear lever (62) downward, depressing the sear and releasing it from the notch of the feed piece.

The bolt head (63), bolt body (64), firing pin, and feed piece move forward under the action of the mainspring, which is encased in the spring tube. The feed piece strikes the upper part of the head of the cartridge in the magazine and forces it forward out of the magazine. At this time the cartridge guide (65) is being held up by the roller working in the cartridge guide cam slot. The bullet is directed into the chamber, the magazine spring forcing the rear end of the cartridge up into the path of the bolt head just as the cartridge is freed from the lips of the magazine.

The cartridge guide cam causes the cartridge guide to drop, thus letting the feed piece pass forward and release the barrel catch (66). The bolt-head stop (67) keeps the bolt head and bolt body at their extended positions so that the locking lugs in the bolt head are vertical, thereby permitting their entrance into the locking recesses. The bolt-head stop then conies out of the breech casing, the bolt head is released and rotates so that the locking lugs engage in the locking recesses in the breech casing to lock the mechanism. The bolt body and firing pin continue to move forward, and the extractor grips the rim of the cartridge as the bolt head turns. The firing pin primes the cartridge just as the feed piece releases the barrel catch.

Backward motion: The recoil from the explosion combined with the action of the gases on the barrel nut (68) carry the breech mechanism and casing in a locked position to the rear against the action of the recoil spring (69) and mainspring. The breech casing and barrel (70) being free to move, immediately start forward. The breech mechanism is held back, due to the sear engaging in the sear notch on the tail of the feed piece. As the barrel moves forward the empty cartridge case is drawn from the chamber by the extractor. As the barrel continues its forward motion the front end of the empty case clears the opening in the breech housing and it is thrown out through the ejection-opening by the pressure of the ejector upon its base. If the regulator is set for single fire the hand sear is immediately released by the trigger bar. This allows the sear to hold back the breech mechanism until the trigger is again pulled. If the regulator is set for automatic fire the hand sear is not released, but is held up 67 64 70 68  FIG. I i. - Chauchat M achine -rifle.

## Chauchat Machine-rifle

The Chauchat machine-rifle, model of 1915 (fig. I I), also known as Rifle C.S.R.G., was designed by a commission presided over by Col. Chauchat. It weighs about 19 lb. and is about 45 in. long. It takes the 8-mm. Lebel cartridge or, in the case of the guns taken over by the U.S. army,' the U.S. model of 1906 ammunition.

This rifle is recoil-operated; the recoil being assisted by deflecting part of the gases as they escape. The cooling of the barrel is assisted I As already mentioned, the Browning gun was reserved until a large supply could be put into line at one time. Pending this, the American forces in France were equipped with the Chauchat of which some 34,000 were adapted to U.S. ammunition.

by the trigger mechanism. The rear cam surface on the bottom of the breech casing strikes and depresses the hand sear just as the barrel reaches its forward position. The hand sear forces the sear lever down, which in turn depresses the sear, releasing it from the sear notch of the feed piece. This allows the breech mechanism to go forward and repeat the cycle.

This rifle is provided with a forward grip (71) for use in marching fire. A bipod (72) is provided for prone or fixed position firing.

Hotchkiss Light Machine-Rifle (fig. 12) weighs 182 lb., is aircooled and gas-operated, magazine-fed, and provided with a bipod (73), a hand grip (74) and a shoulder stock. The general mechanism is the same as in the Hotchkiss machine-gun. The speed regulator and buffer mechanism is especially interesting.

61 The regulation of the speed of the gun is controlled by an escapement mechanism, located in the tube (75), which arrests the recoil mechanism and releases it after the catch has been set free of escapement.

This weapon, like the German light machine-guns described later, and unlike those hitherto dealt with, is derived directly from the heavy machine-gun. It is the outcome, therefore, of an effort to increase the mobility of the machine-gun rather than an attempt to improve the fire power of the shoulder rifle. As a true automatic rifle was available in the form of the Chauchat, and as all facilities for the manufacture of typical machine-gun elements were absorbed by the demand for heavy machine-guns, this type was not manufactured on a service scale during the war. It is however interesting as an instance of the machine-gun approximating to the machine-rifle.

FIG. 12. - Hotchkiss Machine-Rifle (French).

Madsen Machine-Rifle (fig. 13) is a recoil-operated, air-cooled rifle weighing about 16 pounds. It may be fired either semiautomatically or automatically. The rate of fire when used as an automatic is about Soo shots per minute. The barrel is about 23 in. long, somewhat larger in diameter than the barrel of the ordinary shoulder rifle, and is provided with annular rings and a perforated barrel casing to facilitate cooling. A bipod and a rest attached to the butt steady the rifle when used by a firer lying down. The cartridges are fed from a detachable quadrant-shaped, 40-round magazine projecting above the gun.

A detachable barrel is provided for the purpose of gaining a more sustained fire, the system being to replace the barrel, when it has been excessively heated, by another barrel, and continue the fire while the first barrel is being cooled. It is claimed that the barrel may be changed in from 12 to 20 seconds.

FIG. 13. - Madsen Machine-Rifle (Russian).

The action of the mechanism is as follows: - When the gun is loaded, as shown in the figure, and the trigger (76) is pulled, the hammer (77) under the force of the hammer spring (78) strikes the link (19), which transmits the blow to the firing pin and so to the cap. On firing, the barrel (80) and bolt mechanism (81), locked as a unit, recoils, compressing the recoil spring (82) until the link disconnects the bolt from the barrel lock and allows the bolt to recoil sufficiently to cock the hammer, extract and eject the fired cartridge case. The accelerator (83) assists in driving the bolt to the rear as it engages on the accelerator lug (84) during the recoil and transmits the momentum of the barrel and mechanism to the bolt. The accelerator also drives the barrel home during the forward stroke of the bolt.

A safety device (85) controls the trigger. A change lever (86) enables the gun to be fired semi-automatically or automatically.

The Madsen light machine-rifle was designed some years before the war, and for a time all Russian cavalry divisions had automatic rifle sections armed with it. These were abolished before the outbreak of the World War and replaced by ordinary machine-gun sections as the lighter weapon was found to be too delicate for the field. The Madsen was, however, again taken into use by the Russians during the war, and under the name of the " Musket " it formed the armament of the German " Musket battalions " which were created in 1915. Some of these units with their guns were engaged in the battle of the Somme 1916 but apparently the result, in the trying conditions of the trench-warfare battle, was not very successful.' Tests have been made of the Madsen gun at different times in the British and United States armies.

The Lewis Machine-Gun (fig. 14) is a magazine-fed, gasoperated, and air-cooled machine-gun. The ground type, which is used as a light machine-gun, weighs 262 lb., and is capable of firing at the rate of about 600 shots per minute. The ammunition is fed from a drum-type magazine placed over the receiver, and which holds 47 rounds for ground use, or 97 rounds for aircraft use. It was invented by Col. I. N. Lewis of the U.S. army shortly before the outbreak of the World War, and large numbers were purchased by the British Government to supplement the available Vickers (heavy) machine-guns. When the differentiation of light and heavy types began, therefore, the British army found itself already provided with a gun of what was judged to be sufficient mobility, handiness and firepower, and the Lewis gun became and remained the standard type of the light machinegun for the fighting unit of infantry. In the United States, on the other hand, the military authorities determined to adopt the still lighter Browning, and pending the supply of this, the Chauchat as above mentioned. The Lewis gun, thus classed among the heavy machine-guns, was, however, used in large numbers for aircraft, and a few were employed for training purposes as well, some 39,000 of U.S. rifle calibre being ordered and produced. For aircraft, the gun was used by the French also, while in 1918 the Germans, who had a high opinion of it, armed some newly formed motor-cyclist units with captured weapons.

The principal feature is the cooling system, which consists of an aluminum radiator having deep longitudinal fins surrounded by a thin tubular casing which projects several inches beyond the barrel and is reduced in diameter at the front end. These parts with the barrel mouthpiece constitute the cooling system. The mouthpiece deflects the powder gases against the interior wall of the forward portion of the radiator casing in such a manner as to draw a current of cool air through the open rear end of the casing and along the thin fins from which it absorbs the heat. The heat conductivity and low specific gravity of aluminum combined with the construction described produce a light-weight cooling mechanism. The Lewis machine-gun is provided with a bipod mount. The over-all length is approximately 51 inches. The muzzle velocity and chamber pressure are approximately the same with a given ammunition as that of the shoulder rifles in which the ammunition is used.

Action: To operate the Lewis machine-gun, a loaded magazine (Io-I I) is placed in position on top of the gun, and the charging handle (8-4) is pulled to the rear until the sear nose (5-8) engages in the sear notch in the rack (8-i). The gun is then ready to be fired. When the trigger is pulled and held, the rack and piston (8-6) move forward under the action of the mainspring (9-9), which in unwinding rotates its gearwheel (9-7) and rack to carry the bolt (4-4) forward. As the operating rod moves forward, the front top edge of the bolt strikes the lower edge of the cartridge which is held in the magazine and feed-way, and drives the cartridge forward into the chamber. The locking lugs on the rear of the bolt move clear of the guide slots in the receiver so that the bolt is free to rotate. The locking of the bolt is then accomplished by the striker post coming in contact with the left side of a cam slot in the bolt, which forces the bolt and its lugs to turn one-eighth of a turn to the right. The extractor springs over the rim of the cartridge case (or the cannelure if rimless) as the bolt forces the cartridge in the chamber. The magazine is held by the rebound pawl (6-8) during the forward move of the bolt and piston. The feed operating arm (7-5) acted upon by the feed operating stud (4-I) on the rear of the bolt, returns to its normal position during the forward motion of the bolt ready to feed the next cartridge. When the bolt has been completely locked, the striker is free to drive forward and fire the cartridge. When the cartridge is fired the mechanism remains locked until immediately after the bullet has passed the gas port in the barrel (3-I). Thereupon a portion of the powder gases enters the gas regulator cup (3-8) and thence through a small aperture 2 reaches the front of the piston (8-6). The force of the expanding gases drives the piston to the rear and through the action of the rack, rewinds the mainspring (9-9). During the backward motion, the striker post, which is also carried on the rack, moves 1 In 1918 the Musketenbataillone were reformed as ordinary heavy machine-gun units.

2 The function of the gas regulator cup is to act as a well for any solid matter carried in the gas and to prevent fouling of the gas chamber. The size of the aperture can be adjusted as required.

Section on B-B

|   
---|---  
  
about one inch to the rear in a straight slot in the bolt, which, therefore, it does not affect while the bullet is traversing the final space between the gas port and the muzzle; but after the striker post has passed through the straightway of the bolt, it comes in contact with the right side in the cam slot in the bolt and unlocks the bolt and drives it to the rear. In unlocking the bolt is rotated and the locking lugs come into line with the guide slots in the receiver. Lastly the extractor (4-3) withdraws the empty cartridge case which is thrown out by the ejector (2-3), a flat lever pivoted in the centre and actuated by the feed operating stud (4 - I) striking its rear end. This stud, Feed  heavy machine-gun (M.G. 08), which is of the Maxim type, without any change in the essentials of the system (for which see Machine-Gun, 17.237). A serviceable light machine-gun was made in large quantities and with the least possible delay, and the German authorities determined to lighten the existing material, for which manufacturing facilities were already available, rather than embark on the experiments and tool and gauge making that would have been necessary if a new type had been Radiator eed Paw Backeight Cartridge Guide 70-2 Mag. `2-3 (Jo tor 2-1 Recs'uet 4-4 Bolt Magazine 1 {, 70 4-4 Bolt 2Receiver81 StrikerF'xng in  ?g E  ?s+ii 'i,y /y//, ' '??eete,?aa ' '- ..?., ' / i 'Sy 8-1 Rack p !IA Mainspring 84 Handle 4-1 Feed O ,Stud  FIG. 14. - Lewis Machine-Gun.

Section on A-A 5-8 Backsight  A 8-6 Piston gases   ?.? w?l 3Sii??? C a?'eS"x?,l?"s:i

    '?f'.S:'

?1"? r. w, 'sa?S?:i.?'?..x.%?. ?///iiinv/wn./.vorsvi/rri12viiY /N'/H/ //JV// ,,_ which is carried by the bolt, also acts on the underside of the feed operating arm (7-5) and moves the arm to the left. B y means of this arm and the feed pawl (7-2) that it carries, a cartridge from the magazine is brought under the cartridge guide (6-24) and into the feeding position in the feed-way in the top of the receiver and is partially turned so as to bring the next cartridge into position, being held in its new position by the stop pawl (6-7), and by the rebound pawl (6-8). The rearward motion of the mechanism is arrested when the bolt comes against the butt tang of the stock, and the bolt, rack, etc., then again move forward under the action of the mainspring, and the cycle of operation is repeated for each shot until the magazine is empty or the trigger is released. When the last cartridge is fired from the magazine, the bolt goes forward and locks with no cartridge in the barrel.

The magazine is a round corrugated pan about 8 in. in diameter carrying 25 upright separator pins. This pan is mounted with an aluminum centre having annular grooves with a spiral step connecting each groove, into which the front end of the cartridge fits. The cartridge, being held from rotating by the separator pins, is fed along these grooves up the steps into the gun when the pan is revolved around the magazine centre. The pan is loaded by means of a special loading tool. The feeding of the cartridges being positive instead of depending on springs or gravity, the gun can be used when turned at any angle or upside down.

The Lewis machine-gun operates automatically, single shots being fired by quickly releasing the trigger after each shot.

In aircraft the Lewis gun is used as a " flexible gun," i.e., a gun mounted (usually in the observer's pit) so as to fire in any direction in elevation or azimuth. The main differences between the ground type and the aircraft type gun are that the latter has no radiator or radiator casing, has a spade or stirrup-shaped hand-grip in lieu of the shoulder stock, and uses a 97-round magazine. A more efficient type of recoil check is also provided. This consists of a muzzle attachment which is arranged to deflect the powder gases so that they pass out practically at right angles to the axis of the bore. In this way a pressure against the muzzle piece tends to counteract recoil.

No cooling device is provided with the aircraft gun, inasmuch as the fire is in short bursts only and the speed of the aeroplane and the temperature at high elevations provide ample cooling. The aircraft gun fires at a rate of about 750 shots per minute, this higher speed being gained by increasing the gas pressure acting on the piston and the strength of the mainspring which returns the mechanism.

## German Light Machine-Guns 498115 and 08/18

The German light machine-gun 08/15 is simply a modification of the standard sought for. In consequence, the differences between the 08 and the 08/15 are very few. The diameter and contents of the waterjacket are considerably smaller in the light gun than in the 08. Instead of the tripod or sleigh mount, there is a shoulder stock and bipod, and a trigger release and ha.ndgrips replace the twin handles and firing gear. Ammunition is belt-fed as in the heavy gun, but the belt (loo rounds) is wound on a reel inside a drum attached to the right of the gun. The weight of the gun with water-jacket filled and bipod, is 402 lb., or in action with drum and filled belt 512. The Dreyse water-cooled light machine-gun was also used. Its weight was slightly less than that of the 08/15.

Guns of this weight, however, though they might be sufficiently mobile for trench warfare battles, were evidently too heavy for the more open warfare of 1917 and especially 1918, and a new and lighter model called the 08/18 was brought out. In this instead of the water-jacket there is a barrel casing with numerous holes to facilitate air circulation round the barrel. This abolition of positive cooling by water reduced the possibility of sustained fire almost to that of an automatic rifle, but independence of water supply greatly reduced freedom of manoeuvre and the actual reduction in the weight of the gun was considerable (32 lb. as against 402 in the 08/r5).

This gun had been introduced only for cavalry and cyclists when the Armistice was signed. Had the war continued, it would no doubt have replaced the water-cooled weapons entirely.

The Berg'nzann Light Machine-Gun (fig. 15) in the German army, variously called L.M.G. and L.M.G. 15 n A, is a recoiloperated air-cooled, belt-fed machine-gun, weighing 3 o lb. with bipod mount and sling, and fires about 600 shots a minute.

A barrel casing (91) is provided which carries the barrel and also serves as a housing in which the barrel recoils. The cooling Of the barrel is assisted by rings which are formed on the barrel to increase the radiating surface. A handle (92) is provided to facilitate carrying the weapon short distances. The belt is fed through the feed-box opening (93) as in the Maxim and other heavy machine-guns.

The principal features of the Bergmann machine-gun are a small cylindrical service-rifle type of bolt and extractor, which may be operated by hand by means of a bolt handle (95); and an accelerator which is in the form of a cam lever, which acts against the bolt and barrel extension during the forward movement of the bolt, helping to push the barrel extension and barrel forward as the bolt advances under the action of the heavy recoil spring.

The gun is provided with a trigger and handgrip, a shoulder butt and a bipod, which is attached to the trunnion (96).

The front sight (97) is very high, owing to the low position of the barrel in the receiver and to the feed mechanism in cover. A tubular sight with a hole about one-fourth of an inch in diameter is attached by a bracket to the side of the gun for close-range shooting and for tank work. It will be noted that several features of this gun were adopted in the L.M.G. 08/18.

In the German army Bergmann guns formed the armament of the so-called " Light Machine Gun Detachments," mounted units created in 1916 for the Rumanian campaign. The use of this gun, however, seems to have been discontinued towards the end of the war, the weapons remaining serviceable being handed over to Turkey.

## Machine Carbine-Pistols

The idea of securing more accurate shooting from a pistol by fitting it with a shoulder stock and lengthening the barrel is an old one, and one well-known modern example is the Mauser pistol (for description see 21.657-8). But while in the pistol proper, from the nature of the arm and its uses, all modern development has been in the direction of perfecting the semi-automatic action (see PisToL), there arose in the World War a need for some weapon lighter and handier than the rifle yet capable of developing an intensely rapid fire at short ranges. The outcome of this need was a class of firearm which at present has few representatives and no recognized generic title, but is very interesting. In the absence of an accepted designation, these may be called machine carbine-pistols.

FIG. 16.--Bergmann Pistol-Gun.

In this field the precursors appear to have been the Italians. The pistola migliatrice Fiat (Fiat mitrailleuse pistol) was largely used by them as a substitute for the light machine-gun, no doubt because extreme lightness both in the gun and its ammunition was essential in an automatic arm for mountain warfare. The " machine pistol " is fitted with a small shield which also serves as a mounting, though the weapon can be used in the hands, if necessary. It is double-barrelled, each barrel having a separate box magazine of 25 rounds above the receiver. It is gas-operated and air-cooled. The bolt and its dependent parts are supported but not positively locked on firing. It weighs r4 lb. without shield, takes 9 mm. pistol ammunition, and is sighted to 50o metres. An outstanding feature is the very high rate of fire. Both magazines (50 rounds) are fired in two seconds, and with highly trained loaders and a full supply of magazines it is said that i,000 rounds can be delivered in a minute. This extreme rate, in spite of certain advantages, militates against steadiness and accuracy, especially with so slight a mounting. Nevertheless, according to the Germans the weapon proved trustworthy and effective.

The Bergmann Pistol-Gun (fig. 16), on the other hand, was intended not to replace the light machine-gun but to provide artillerymen and machine-gunners with a handy personal weapon capable of intense fire power in emergencies. It originated in the pistol proper. The German service pistol 08 (BorchardtLuger) used by specialists, who were not armed with the rifle, was fitted with a snail magazine (see Pistol) allowing of 32 shots, the wooden holster being attached to the handgrip as a shoulder piece as in the Mauser pistol above alluded to, if accurate fire was required. The success of this arrangement led to the introduction of the Bergmann pistol-gun (officially, Machine-Pistol 18 I.), which in spite of its name is rather a carbine than a pistol, as an infantry weapon pure and simple.

This arm shoots 9 mm. pistol ammunition at the rate of about 540 shots per minute. The gun weighs 9 lb. 6 oz. without the magazine drum, which itself weighs I lb. 8 oz. empty. It is recoil-operated and air-cooled, and has an 8-in. barrel, protected by a casing perforated to allow circulation of air. The magazine (32 shots) is of the snail type (see Pistol). The breech mechanism is of the " blow-back " class in which on firing the inertia of the bolt, the compressing of the mainspring, and friction of the cartridge in the chamber momentarily hold the action firm. The gun fires when the bolt reaches its forward position as the striker projects through the face of the bolt, and is cocked when the mainspring is compressed and the bolt drawn to the rear. This has the advantage that the chamber is always left empty, but the forward movement of the heavy bolt after pulling the trigger is liable to disturb the aim. The gun is sighted to 200 metres only.

This gun was only brought into use just before the Armistice.

The Thompson Sub-Machine-Gun (figs. 17 and 18) is an interesting type of a very light portable automatic weapon which shoots a 45-calibre pistol cartridge. The action is semi-automatic or automatic at will. The rate of fire when used as an automatic is Boo to 1, 50o shots per minute. The weapon is about 23 in. in length, weighs 7.5 lb., and uses a straight magazine (fig. 18) holding 20 cartridges in staggered rows, or drum magazines holding 50 or loo cartridges (fig. 17).

The novel feature of this weapon is the angular wedge breech closure which utilizes the force of adhesion developed by the heavy breech pressure to lock the breech. The principle, developed by Comm. Blish of the U.S. navy, has been briefly stated as follows: " In any breech closure consisting of a breech plug in a suitable housing and having two pressure-resisting surfaces, the forward surface disposed normally to the axis of the bore, and the rear surface inclined thereto and bearing upon a suitable surface of the housing, the force of adhesion will under heavy pressure immovably fix the breech block, but at a comparatively small pressure (whose value depends upon the inclination of the two surfaces) the force of adhesion ceases to act and the breech block is rendered free to move under t he influence of the forces then existing." The principle permits the use of a very simple breech-locking mechanism, the essential element being a bolt (98) having an angular slot cut in the under side, into which the lock (99) is free to slide, and a housing or receiver (ioo) having a slot (101) into which a projecting lug on the lock engages when the bolt is in its firing position. Under high pressure the lock firmly adheres to the receiver shoulder and FIG. 15. - Bergmann Light Machine-Gun.

'?'?ti ?..  _.?

Treed sic. - 98  ? i' er? \ `l\\\a`hm?` Qi??' ,--_ - -  FIG FIG. 17. Thompson Sub-Machine-Gun.. 18.

S I?R ? ??

prevents the bolt from being blown to the rear. When the pressure is reduced, the adhesion ceases, and the lock, actuated by the remaining pressure, automatically slides upward and clear of its retaining shoulder while the bolt moves rearward against the recoil spring (102) and cocks the firing pin.

When the weapon is cocked the entire bolt group is held by the sear (104) in a retracted position, as shown in fig. 17. On the trigger being pulled the bolt, driven forward by the recoil spring, pushes a cartridge into the chamber. During the forward motion of the bolt the hammer (103) strikes a shoulder of the receiver and rotates on the hammer pin, its top end strikes the firing pin and the cartridge is fired. Firing is discontinued by releasing the trigger; the sear (104) then engages the bolt in its retracted position, leaving the chamber empty. By means of the disconnector (105) the weapon can be made semi-automatic at will. When the magazine is emptied, the trip (106) allows the sear to engage the bolt in a rear position ready to feed and fire again when the trigger is pulled. Sights graduated to 600 yd. are provided.

The sub-machine-gun is intended as an auxiliary weapon for trench use and for close fighting generally. It has been adopted also by the police of several American cities for use as a riot weapon, both for shot and ball cartridges. (H. O'L.)