This section presents a detailed examination of the German Maxim Machine Gun, Model MG 1908 and MG 08/15 as they were deployed on the battlefields of World War I.

As part of a program to update the original Maxim system adopted by German forces, engineers re worked the 08 pattern with an goal of making the gun lighter and more mobile. The result was the MG 08/15. Externally they are similar but with true German efficiency internal parts (recoil plates, cross head, locks and barrels) are interchangeable.

The Maxim gun consists of several major components, each of which is displayed below in detail.

The Receiver of the '08 consists of a three-sided box constructed of sheet metal of 0.143in thickness. This in turn is made of three riveted plates (two sides and a floor plate). These plates are of mildly hardened steel to protect the internal parts from being disabled due to dents and bending. Although hard enough for general handling they do not provide a bulletproof protection as exhibited by several battle damaged specimens in the USMCM collection.

This three sided housing has an oval cam riveted on the inside (upper center) of each side plate which provides the method for the bolt or lock to cycle in an up and down action. This cam action drives the bolt to extract a round from the feed block, inserts the new round into the chamber, fires then ejects the spent casing.

The receiver floor plate has the mounting for the trigger bar, which provides the trip mechanism for the cycling bolt.

The 08 receiver plates also have the required cutouts to support the feed block

The receiver is mounted to the water jacket and the gun trunion via a pair of dove tailed keyways riveted to the side plate. These keyed tracks slide down onto corresponding dove tailed grooves the water jacket housing until two-holes line up in the forward end. Through these holes a pair of pins pass through the truing locking in the receiver truing.

The rear of the receiver box has two keyed pinholes through which the rear spade grip and trigger mechanism is mounted. These pinholes are of a quick release type so that the rear of the gun can be quickly opened without requiring major tools.

The receiver of the MG 08/15 functions basically the same as the MG 08 however, there were changes in the construction aimed at making the gun less cumbersome.

The 08/15 receiver is constructed of three plates riveted together along the floor plate. However the keyway was no longer used for assembly to the water jacket. The 08/15 receiver plates are assembled to the trunion and water jacket by a series of rivets and an overlap seam.

The cutout for installation of the feed block is no longer in the receiver side plate rather it is incorporated in an extension of the water jacket housing which extends back past the trunion.

The trigger mechanism was reengineered. The 08 spade grip was abandoned on the 08/15, replaced by a rifle but stock. The trigger was moved to a pistol grip extension bolted to the bottom plate. This new trigger extension controls the trigger bar. There is a return spring incorporated in a mounting pin attached to the floor plate to return the trigger to the non-firing position when released.

The ejector tube found in the 08 receiver was also eliminated. The spent shell casing ejected through a hole in the bottom front of the water jacket extension.

A final modification of the 08/15 receiver included a cut out in the back top of the receiver and a narrowing of the overall width. This was part of the effort to reduce the size as well as make the 08/15 lighter.

The water jacket provides a mount for the barrel and a method of cooling the gun while it is in action. The jacket contains a chamber through which the barrel passes, allowing the barrel to move forward and backwards as the gun cycles through its firing sequence. The jacket is also filled with water cooling the barrel while in operation. .

The fluid is retained during operation by a packing ring on both the muzzle and the breach of the barrel. The ring is fitted into a grove machined on the breach of the barrel into which the packing is wound. This in turn is closely fitted into the trunion. As the barrel cycled forward and back with the recoil action, the barrel slides in the trunion with the packing keeping the cooling liquid from escaping to the rear. The front packing is at the point where the barrel exits the cooling jacket. This packing is retained in its seat by screwing in the forward flash/booster mechanism or by use of a muzzle gland nut. The compression of either of these expands the packing making a waterproof seal at the forward end of the gun.

To drain the coolant from the gun there is a drain petcock. The water jacket is also fixed with a filler point to add coolant during operation. The jacket also has a connection for a steam hose. Although it has been a common error in thinking that this steam hose provides for circulation (much like that of an automobile) it is not so. The purpose of the steam hose is to collect steam generated by the hot barrel in it s water bath and route it to a collection can. The objective here is to mask the position of the gun. The white plume of steam is a dead giveaway of the gun's position. Condensed steam collected in the can may be re pored into the water jacket if necessary.

Inside the water jacket the barrel floats free, the cooling liquid coming in direct contact with the barrel and keeping it cool while firing. In addition there is a device in the jacket running along the top under side of the housing. This device is a steam collector. It provides the gun with the ability to fire up and down at extreme angles without the liquid being directly exposed to the steam hose vent. It consists of a brass tube with an inner sliding tube. So that if the gun is tilted upward the inner tube slides to the rear of the jacket, closing off the steam entry hole at the back of the jacket and opening the steam entry hole at the forward end. Thus cooling liquid is trapped at the back of the run, the seam vents at the forward end.

The cooling jacket also is fixed with the mount for the front sight. Standard issue is a dove tailed blade site, which may be adjusted left and right by removal of a screw pin and It tapping it into position. The front sight may also be changed to an anti aircraft sight. The AA sight fits into the dovetailed groove that holds the standard blade sight.

As mentioned in the previous section the barrel is not permanently fixed to the gun or the receiver. It is allowed to float during the operating cycle in a forward and back motion. This is the recoil feature of the Maxim. As the gun fires, the recoil action of the barrel uses the energy of the rearward motion to cycle the gun through its firing sequence.

The barrel has a packing groove on the rear end, with a large brass recoil collar fixed to the barrel. There is no provision for head spacing at this point. The cartridge is completely chambered in the barrel. The back end of the barrel is formed into a block with tracks for the lock to slide up and down through. On the side of the rear block are two flat studs. These are used to connect (like the trunions of a cannon) the barrel to the rails.

There are two side rails or recoil plates in the Maxim receiver. They consist of two flat bars, mounted to run parallel to each other just inside of the receiver side plates. They are not attached to the receiver and like the barrel float free in a forward and backward motion between the side plates. These rails serve as a link, attaching the barrel to the other working components and provide the mounting for the lock. The rails transfer energy from the recoil motion to operate other parts of the gun. Sliding in close tolerance grooves on the rails the lock moves forward and back, pulling a new cartridge from the feed belt, inserting new rounds into the breech, re-cocking the firing mechanism, and then extracting the spent cartridge.

The left rail is longer than the right. This extension is fixed with a notch into which an operating lever from the feed block is fitted. As the barrel and rails cycle forward and back the operating lever on the extended rail transfers energy to the feed block mechanism. This action causes the feed-block to pull in the ammunition belt with the next cartridge into position so the lock can pick it up as it passes through the firing cycle.

The rails also are the points where the coiled Fusee spring is attached. It is this spring which returns the barrel to the forward position after the rearward cycle is complete.

This mechanism is fixed on the right side with a cocking handle. A rotating shaft passes through the right hand recoil plate to the left hand recoil plate. On the left hand side of this bar is a toggle to which the fusee spring is attached. Between the recoil plates on the shaft is a socket into which the interrupted screw post that connects the lock to the shaft . These are fixed together with close tolerance fitted joints, keyed with driven pins.

Note: Recoil plates, cocking handles, swivel shafts, cross head and fusee links are all interchangeable between the 08 and the 08/15 guns.

The front portion is slotted to match the rim of the cartridge case. During operation this moves in a up and down motion providing a method of grabbing cartridges from the feed mechanism and holding it until it has been inserted into the breach of the barrel. At the same time it grips the spent cartridge extracted from the barrel until it can be passed into an ejection port.

Note: During the normal cycle there are usually three cartridges being held by the forward part of the lock. One to be extracted from the feed belt, one in the chamber ready for firing and one in the ejection sequence. This is why it is important to cycle the gun for a minimum of three cycles of the cocking lever to ensure all cartridges have been expelled from the weapon.