A 4-Part Article from "Engineering" 1898. The first part is taken from Engineering, February 11 1898, pages 164 to 167. In this first part, Maxim describes his many ideas for automatic machine guns, which he then patented to ensure other inventors could not capitalise on his inventions. The figures have been interspersed within the text to improve clarity. Transcribed by rob.b1904 (March 2011).

The Maxim Gun - No 1. (Engineering, volume 65)

The Origin of the Maxim Gun

As we purpose giving a somewhat full description of the Maxim gun as it now exists, it will be interesting and convenient if we describe all the steps by which this most remarkable gun has been brought to its present state of development. There has been a good deal of argument as to whom should belong the credit of having first suggested an automatic gun. Into that question we do not propose to enter; for, like most controversies of a similar nature, it is altogether profitless. A good many personal motives of a not altogether creditable sort appear to have been involved in the dispute; but whatever may have been the vague suggestions of previous speculations on the possibility of an automatic-firing gun, we believe there can be no doubt but that to Mr. Maxim belongs the credit of having produced the first practical automatic gun.

The engravings on pages 166 and 167 [Figures 1-20, 22 from page 166, Figs 21,23,24 from page 167 – however, in this transcription, the figures have been interspersed within the text] show some of the early forms of Maxim gun, and well illustrate the familiar process of invention and rejection which new mechanical devices nearly always go through. We have already given in these columns an account of the steps which led Mr. Maxim to turn his attention to the production of an automatic gun . How the kick of an ordinary rifle first impressed him with the idea of wasted power; an idea that was further worked out when he found himself, a year or two later, in Paris, with not enough occupation to fill up his time; and how the first successful automatic gun was produced in Hatton Garden at a still later date. This ground we need not go over again in dealing with our present illustrations.

Mr. Maxim divides automatic guns into three classes. In the first the whole of the arm, or the barrel and mechanism, recoil at the instant of firing, the energy of this recoil being utilised for performing the functions of loading and firing. In guns of this type the moving parts, which are set in motion by the discharge and participate in the recoil, are actuated by coming in contact with some stationary point of resistance. The latter may be the shoulder of the gunner or the carriage or mounting of the gun. A certain number of the functions may be performed while the barrel is moving; such as, for instance, the opening of the breech, the cocking of the hammer, and the extraction of the empty cartridge case. A portion of the energy may be stored in the momentum of the moving parts or in coiling certain springs which again give out the energy and perform other functions, such as removing the cartridge from the magazine, putting it in the chamber, closing the breech, and pulling the trigger.

In the second class the cartridge, or a portion of the cartridge, moves back in the chamber at the instant of firing. For instance, it may be supposed that a cartridge is allowed to move to the rearward a short distance while the high pressure is still in the barrel. The energy produced may be utilised for performing all the functions of loading and firing. This class of gun may be again divided into several sub-classes : in some the cartridge case itself would move to the rear; in others only a portion of the case, or a piston in the case, would do so, whilst again the cartridge case might be corrugated so that it could be elongated by the pressure of the powder gases. It has been found by experiment that British service cartridges, having 85 grains of powder, may be made to operate a gun successfully if elongated by the explosion 1/64 in.

To the third class of automatic gun Mr. Maxim assigns what may be called piston-guns. They are operated by the gases escaping from the barrel. An example of this type is afforded by an arrangement in which a cylinder is placed parallel to the barrel; there being a small passage for admitting a portion of the gases to escape from the barrel, these gases operating a piston, thus giving the required motive power. If the piston were small and light, if it were placed very near the bore of the gun, and if it were worked parallel to the axis of the barrel, it would not disturb the arm to any appreciable extent. But Mr. Maxim has found that if the piston be of considerable size, and is placed some distance from the barrel, the disturbance becomes very great, so much so that it is impossible to do accurate shooting with such a weapon. The gases, however, may be allowed to expand in a cylinder which is attached to the gun or carriage, and the barrel may be provided with a piston which could be pushed backwards, or the cylinder may be pushed forwards, at the instant of firing. The cylinder and piston being co-axial with the barrel, and the movement being parallel to the axis, no disturbance takes place. This arrangement does not necessitate the boring of holes in the barrel.

Referring now to our engravings [on pages 166 and 167] - which, with the information respecting them, have been kindly supplied to us by Mr. Maxim - Fig. 1 is taken from a patent of Mr. Maxim's of 1883, and shows an arrangement in which the barrel and the mechanism are locked together at the instant of firing. The recoil brings the arm back against a stationary heel-piece resting on the shoulder of the gunner. The heel-piece being pressed forward in relation to the gun, operates the mechanism which performs all the functions of loading and firing. This arrangement was designed to be applied to the Winchester gun.

In Fig. 2 is shown a plan which Mr. Maxim patented in the following year, namely, 1884. The engraving illustrates the elements of a machine gun in which the barrel is locked to the breech-block by a hook. As the barrel and mechanism recoil the hook is made to let go by coming in contact with a stationary point of resistance, and the barrel is brought to a state of rest at the expense of throwing the bolt of the gun violently backwards. The breech-block carries a lever F, which, on recoil, strikes the stationary resistance G, which is thus made to drive the rod E and the breech-block backward. The crank is thereby turned, as shown by the dotted line. The lever I, which locks the breech-block to the barrel, is disengaged by turning about its axis during the recoil. A large number of rounds were fired from a gun on this principle at the Inventions Exhibition of 1885.

Another arrangement patented by Mr. Maxim in 1883 is illustrated in Fig. 3. Here the barrel is stationary, a small and short rimless cartridge being employed. The backward motion of the cartridge is opposed by the inertia of a weight, which, being very much greater than the projectile, moves slowly backwards and performs the functions of loading and firing. Fig. 4 shows another arrangement patented by Mr. Maxim in the same year, in which the rearward motion of the cartridge is also opposed by a weight which is attached to a toggle-joint in such a manner that the weight has to move much further than the cartridge. This allows a smaller weight to be used than would be otherwise required for opposing the rearward motion of a strong cartridge.

In Fig. 5 the cartridge is made in two pieces, that part which carries the primer being actually a piston working air-tight in the cartridge case proper. The backward motion of this piston at the instant of firing develops the necessary energy for loading and firing the gun. A too-rapid rearward action of the piston is prevented by a weight and toggle-joint. Two patents were taken out by Mr. Maxim for this device - one in 1883 and another in 1884.

In Fig. 6 a corrugated cartridge case is shown. The elongation of the cartridge at the instant of firing sets a weight in motion by means of a toggle-joint, the necessary energy to perform the function of loading and firing being stored in the weight.

We now come to a device of a different nature. In Fig. 7 is shown a piston-gun operated by the gases escaping from the barrel. The pressure of the gases pushes the lever backwards, raises the bolt, and disengages it from the framework of the gun, and then throws it violently backwards. It may be added that this is a gun of a type that was patented by Mr. Maxim in 1883 and 1884. The engraving shows a modification of a French patent. This modification is also shown in other Continental patents taken out by Mr. Maxim in 1884. In Fig. 8 is shown a different means of carrying out the same general principle. In this gun, the gases, in escaping from the muzzle, expand in a cylinder over the muzzle as shown. There is a hole in the cylinder considerably larger than the bullet, so as not to interfere with the firing. The expansion of the gases throws the cylinder forward, and by means of the bell-crank lever and cam performs the necessary functions of loading the gun. This arrangement was patented by Mr. Maxim in 1884, and it is interesting to notice that in the English patent the system was described as being suitable for application to the Colt magazine rifle.

Fig. 9 shows still another modification of the same principle patented during the same year. The gases escaping from the barrel near the muzzle enter a cylinder and actuate a piston, the piston – rod being connected by levers to the mechanism of the gun. This is also referred to as being applicable to the Colt magazine rifle. In Fig. 10 there is placed over the muzzle a sleeve which is driven forward by the gases at the instant of firing, the barrel remaining stationary.

In Fig. 11 the gases escaping from the barrel impinge upon two curved levers, which, moving in opposite directions, prevent the gun being deflected. In Fig. 12 there is attached to the barrel, as shown, a lever upon which the gases impinge and thus supply the motive power for working the mechanism. Fig. 13 shows a cylinder arrangement. The gases, when escaping, drive the air out of a tube immediately in front of the barrel, thus producing a partial vacuum. The pressure of the external air in rushing into the vacuum operates a piston which in turn gives motion to the mechanism. All these latter devices were patented by Mr. Maxim in 1884.

An arrangement containing new features was patented in 1890, and is shown in Fig. 14. In this a nose-piece having a contracted outlet is placed over the muzzle of the gun. This nose-piece, being attached to the stationary and non-recoiling part of the gun, the barrel itself becomes the piston, and is forced backwards by the pressure of the gases between the end of the barrel and the nose-piece. This apparatus has been extensively employed for operating Maxim guns with blank cartridges. The movement of the barrel rearward brings a cam against a stationary point of resistance, and rotates the crank of the gun. A modification of this arrangement is shown in Fig.15, which illustrates a device used for firing steel projectiles. As these are too light to produce the necessary recoil, a nose-piece is provided, a small piston being attached to the muzzle of the gun. As the discharge takes place the gases, striking the inside curved surface of the cap, are deflected to the rearward, at the same time causing a high pressure, which forces the barrel backwards, and performs the necessary functions of loading and firing. The nose-piece is firmly attached to the non-recoiling portion of the gun. Fig. 16 illustrates the subject of another patent, taken out in 1890. In this case the barrel is stationary, the cylinder being attached to the muzzle. The piston has a sliding-rod provided with a piston having a sharp edge, this edge being employed for scraping away incrustations in the cylinder. This device worked successfully with black powder, and was used on the first successful gas-operated gun, with a non-recoiling barrel.

A modification of the same principle was experimented with at the Maxim Nordenfelt Works, and was incorporated in the same patent. This is shown in Fig. 17. The mechanism is operated by the pressure set up by the escaping gases, between the end of the barrel proper and what might be considered a false or moving barrel, the latter not being rifled. The pressure of the gases throws the front end of the barrel forward, performing the necessary functions of loading and firing.

We now come to a gun in which water is employed. This is illustrated in Fig. 18, which is from Maxim's patent of 1884. The gases escaping from the barrel produce a high pressure on water in a small cylinder, thus forcing a piston backwards. A larger piston working in a larger cylinder attached to the same rod sucks a certain quantity of water in at each discharge, and, on the return of the mechanism, forces a quantity of water equal to the difference in volume of the two pistons into the barrel. This arrangement was intended to be used with black powder, it being believed that the water would prevent fouling, and also, to some extent, lubricate the barrel.

An arrangement for which a patent was taken out in 1887, is shown in Fig. 19. In this case the gun recoils with the breech closed. It was found that with large cartridges, such as 3-pounders and 6-pounders, the breech should not be opened while the gun was recoiling, because a considerable quantity of gas would then escape. The breech, therefore, as stated, remains closed during the recoil; but, when the gas has all escaped, the gun, in returning to the firing position, strikes a pawl attached to the non-recoiling portion of the gun. The pawl, acting upon a suitable cam, rotates the action-shaft, opens the breech, throws out the cartridge case, and compresses the spring. When the cartridge is in the barrel it releases the action, which again closes. The rearward motion of the barrel is opposed by an hydraulic buffer.

Another patent taken out the year previously covers the arrangement shown in Fig. 20. This was intended for very large guns, the opening of the breech being performed by an hydraulic cylinder. During the recoil of the barrel the water displaced by the piston-rod of the hydraulic buffer enters a similar cylinder placed at the top of the gun. When the gun returns into the firing position a valve attached to the piston prevents the water from returning to the front side of the piston. The water is therefore all driven out of the cylinder below, and, being forced into the cylinder on the top side of the gun, forces a crosshead backwards, first unlocking the breech, and then allowing the gun to return again into the firing position. As the gun returns into the firing position, the piston, by uncovering the port through which the water has passed into the small cylinder, allows the water to be again sucked out of the small cylinder, which action permits the breech-block to return into the firing position.

Another patent was taken out in the same year for the device illustrated in Fig. 21. In this arrangement the gun and the breech-block recoil together, the breech-block being retained in its extreme rearward position, while the barrel returns into the firing position. The hook may then be disengaged, and this will allow the cartridge to be forced into the barrel and the gun to be fired. In this arrangement the gun stops firing with the cartridge out of the barrel instead of when it is in the barrel. The breech-block is held in the closed position by the shoulder A engaging with the abutment B, which forms a part of the shoe of the gun.

Fig. 22, shows an arrangement patented in 1888. In this case a heavy weight participates in the recoil. The gun is brought to a state of rest by hydraulic buffers; the energy stored in the moving weight operates upon the breech mechanism, opening the breech and extracting the empty case. This device was intended for use with semi-automatic guns.

In Fig. 23 is shown one of the systems (several are covered by Mr. Maxim's various patents) introduced for working a pair of barrels automatically. Two sets of mechanism are employed, one moving backwards by the energy derived from the powder gases as the other moves forward, thus affording a means of operating the mechanism. In Fig. 24 the end of the barrel has two diameters, a series of slots being cut through to the bottom of the rifling, as shown. The nose-piece being secured to the water-jacket, the barrel is driven back by the pressure of the gas. We believe that very accurate shooting can be made with guns of this system.