Recently a new dual-purpose machine gun has appeared which may eventually replace the M.G. 34 in the German Army. Like the M.G. 34, it can be used on a bipod (see fig. 49) as a light machine gun, on a tripod as a heavy machine gun, as an antiaircraft machine gun (on a special tripod), and for numerous other special purposes on special mounts. Because of the wide use of stamping, welding, and riveting, this gun is far easier to manufacture and less smooth in finished appearance than the M.G. 34. It is, however, equally as serviceable as the older model, which is still the main armament of all types of German units. A new and faster method of barrel change is another outstanding characteristic of this new model. The rate of fire has been increased over that of the M.G. 34, but a certain decrease in accuracy has resulted.
Figure 49.—M.G. 42.
b. How to Identify
The M.G. 42 may be identified by—
(1) Rectangular shape of receiver and barrel jacket.
(2) Barrel jacket opening on the right side to allow change of barrel. (This change is effected by a handle, also on the right side.)
(3) Operating handle much larger than that of the M.G. 34 and grooved for the fingers.
(4) Leaf rear sight sliding on ramp (unlike the M.G. 34 rear sight, which is of the upright leaf type).
(5) Separate antiaircraft rear sight hinged on the right sight base.
(6) Bolt of a different pattern from that of the M.G. 34, the body being round and having a separate bolt head of a nonrotating type.
(7) Single trigger. (The trigger mechanism is not equipped with two triggers as in the M.G. 34, and the gun cannot fire semi-automatically.)
(1) General.—The M.G. 42 is a combination short-recoil blowback weapon. Instead of the rotating bolt action of the M.G. 34,12 the bolt is locked to the barrel by means of two movable locking studs, located in the bolt head, and operating on two locking cams on the barrel extension. These locking studs resemble a wheelbarrow wheel and axle, and are placed symmetrically in slots in the sides of the bolt head with their axles vertical. The edges of the wheels are in contact with the operating surfaces of the locking cams in the barrel extension. As the bolt closes, the locking cams force the locking wheels outward, so that their axles, which project above and below the slots, enter the corresponding slots in the barrel extension. The barrel is then locked to the bolt head. On firing, the barrel extension and the bolt recoil together a half inch, and then the locking cams serve to unlock the locking wheels from the barrel extension, while the blowback pressure from the barrel drives the bolt to the rear, operating the weapon. This system gives a high rate of fire, which is what the Germans seem to be seeking in this weapon.13
The feed is the same as for the M.G. 34, a belt or drum being used (fig. 50). It
is not known whether a special feed cover to take a
Figure 50.—M.G. 42 with feed cover raised to show feed mechanism.
(2) Table of characteristics.—
|Principle of operation||_ _ _ _ _ _ _||Combination short recoil and blowback.|
|Caliber||_ _ _ _ _ _ _||7.92-mm (.312 inch).|
|Rate of fire (cyclic)||_ _ _ _ _ _ _||1,050 to 1,350 rounds per minute.|
|Ammunition||_ _ _ _ _ _ _||All types of 7.92-mm not expressly forbidden for use in the machine gun (for example, the Patr. 318 manufactured for the Pz.B. 39 antitank rifle is unsuitable, because it will not fit in the chamber).|
|Type of feed||_ _ _ _ _ _ _||1. Non-disintegrating metallic-link which holds 50 rounds and may be connected to make longer belts.|
|Weight as light machine gun (bipod)||_ _ _ _ _ _ _||25 1/2 pounds.|
|Front||_ _ _ _ _ _ _||Inverted V adjustable for height, on a folding post.|
|Rear||_ _ _ _ _ _ _||Leaf with open V notch sliding on ramp, graduated from 200 to 2,000 meters (219 to 2,187 yards) (there is an antiaircraft rear peep sight hinged on the open rear sight base).|
|Auxiliary||_ _ _ _ _ _ _||Antiaircraft ring sight, kept in the maintenance kit, and fitting on the barrel jacket. (This is used in conjunction with the folding antiaircraft rear peep sight attached to the rear sight base.)|
d. How to Operate
(1) Safety.—There is a plunger-type safety catch located just above the pistol grip. Unlike the M.G. 34 safety, it works from side to side. The safety catch cannot be operated unless the gun is cocked. To put the gun on "safe," push the safety catch toward the left (facing the muzzle), until the letter "S" (sicher—"safe") shows on its surface. To put the gun on "fire," push the safety catch toward the right until the letter "F" (Feuer—"fire") is exposed.
(2) To load and fire.—(a) Using belt from belt box.—Insert the tab of the belt, with the open end of the links down, in the feedway on the left side of the receiver (if there is no tab on the belt, take two cartridges from the end of the belt and use the empty links as a tab). The feed cover may be either open or closed during this operation. Pull the belt through until the first round can be engaged by the feed pawls (a three-cartridge width). The cartridges in the belt should not be pulled so far as to cover the feed opening in the feed-plate lower assembly. Do not cock the gun until ready to fire. When ready to fire, cock by pulling the operating handle to the rear as far as it will go. The handle should then be shoved forward again until a "click" is heard. This will prevent a misfire, since the recoil (return) spring is not powerful enough to close the bolt and at the same time to shove the operating handle forward. The safety can be put on "safe" only when the gun is cocked. To fire, move the safety to "fire," and press the single trigger.14 There is no double trigger (to give provision for semiautomatic fire) as in the M.G. 34.
(b) Using 50-round belt from drum.—Press the catch on the sliding cover of the drum, and move the cover to the open position so that the tab end of the belt can be pulled from the drum. Insert the tab in the feedway, with the open end of the links down. Engage the hook which is on the front (narrow) end of the drum onto the lug on the front end of the feed-plate lower assembly.
Turn the rear end of the drum toward the gun until the spring catch on the rear end of the drum engages the lug on the rear end of the feedway. Now proceed as in belt-loading from a belt box (see d (2), on the opposite page).
(c) Using 75-round double drum (if furnished with gun).—If this type of drum is
found with the gun, more than likely the gun will be fitted to take these drums without any
changes, that is, with a special feed cover. This special feed cover has an opening to take
(d) Immediate action.—If the gun fails to fire, pull the operating handle to the rear and return it to its forward position. Then pull the trigger. About the only types of stoppage that will occur in the M.G. 42 are caused as follows: (1) by empty cases jamming in the catch between the bolt and the operating handle, or (2) by empty cases jamming between the bolt head and the barrel extension. To clear the first type of stoppage, the bolt must be drawn back a little by pulling back on the operating handle, holding the bolt level with the feed-arm roller, and moving the operating handle back and forth. To clear the second type of stoppage, merely hold the bolt back and shake the gun several times. This stoppage cannot be cleared by pushing in the end of the bolt or by using a stick or other object to remove the jammed case.
(3) To unload.—To unload (using the belt drum or belt), cock the gun by pulling the operating handle to the rear, and set the safety lever to the "safe" position. Raise the feed cover by pushing forward the feed-cover catch (at the rear end of the feed cover). Remove the belt from the gun. After checking to be sure that the chamber is empty, close the feed cover, move the safety lever to the "fire" position, and ease the bolt forward by holding the operating handle and squeezing the trigger.
To unload when using the 75-round double drum, proceed as in unloading with the belt or belt drum, except that the double drum must be removed before the feed cover is opened.
(4) To change barrels.—(a) General.—The barrel on this gun should be changed after firing 250 rounds in full-automatic fire, or, in cases of emergency, after firing 400 rounds. Spare barrels are regular equipment with the M.G. 42 and are carried in either single- or double-barreled containers by the gun crew. The single-barreled container opens up so that the hot barrel can be laid on it and exposed to the air to facilitate cooling.
(b) Procedure.—Cock the gun and set the safety catch to the "safe" position. Push the barrel-change lever forward, and rotate the rear end to the right and forward (see fig. 51). This will bring the rear end of the barrel clear of the barrel jacket, and it can be withdrawn by grasping it with the asbestos hand pad furnished with maintenance kit. Place the cool barrel in the loop of the barrel-change lever, and seat the muzzle of the barrel in the front end of the barrel jacket; then swing the barrel-change lever toward the barrel jacket until it locks in place. Set the safety catch to "fire" and recommence firing.
Figure 51.—M.G. 42, showing method of operating barrel extension.
The same type of ammunition may be used in both the M.G. 42 and the M.G. 34. (See par. 12e, p. 78, above.)
(1) Oiling and cleaning.—Like the M.G. 34, the M.G. 42 is sensitive to dust, dirt, and sand. To function well, this weapon must be kept cleaned and oiled at all times. The ejection port should be kept closed whenever the gun is not actually firing. The ejection-port cover will open automatically whenever the trigger is pulled back. The tracks on which the bolt slides should be oiled carefully. The bolt head and bolt parts should be oiled lightly. Otherwise, normal care, such as given U.S. automatic weapons, will suffice.
(2) Stripping.—(a) To remove bipod.—Compress the spring catch on the bipod. Rotate the bipod forward, and remove it from the gun.
(b) Feed cover and feed biock.—Release the feed-cover catch (located at
the back end of the feed cover) by pushing it forward. Raise the feed cover to
(c) Shoulder stock.—Press the catch located on the underside of the plastic shoulder stock. Give the shoulder stock a quarter turn (in either direction) and then remove.
(d) Buffer housing and return spring.—In removing the buffer housing, the large recoil, or return, spring will be released. Therefore, care should be taken to maintain pressure on the buffer housing while removing it. Press the buffer-housing catch, which is located beneath the rear end of the receiver just back of the pistol grip, turn the buffer housing clockwise 180 degrees (one-half turn), and ease the buffer housing away from the receiver, releasing gradually the tension on the return (recoil) spring.
(e) Bolt.—First, press the trigger; then strike the operating handle toward the rear with the palm of the hand, thus bringing the bolt to the rear. Withdraw the bolt from the open rear end of the receiver, if necessary, by pushing with the finger.
(f) Barrel.—Proceed as stated in d (4), p. 91, above.
(3) Assembly.—Assembly is carried out in the reverse order of that used in the stripping process. The following steps should be checked when putting the bolt assembly back into the receiver. Insert the bolt head, being sure that the heel of the firing pin (which is on the bolt housing) is on top. The feed-arm operating stud should also be upward, and the extractor should be on the bottom side of the bolt.
Not all the accessories of the M.G. 42 are known, but they are probably similar to those of the M.G. 34.
12 See note 7, p. 58, above.
13 This increased rate of fire is not desirable from any point of view except that of use as an antiaircraft machine gun, because the accuracy is decreased considerably.
14 See fig. 5, p. 8, above, for the method of aligning German sights. See par. 12d (3) (b), p. 64, above, for a description of the telescopic sight which may also be used with the M.G. 42.