Machine gun manual

by H. Douglas

1. Temporary.

Due to (a) Failure of some part of the gun of which a duplicate is carried, or faulty ammunition; (b) neglect on the part of member or members of the detachment. A high standard of training will avoid this.

2. Prolonged.

Due to failure of some part of the gun which cannot, as a rule, be put right under fire, or without skilled assistance.

In addition to the instructions in the “stoppage” table, the following points should be observed:—

1. If, when the cover is opened to investigate cause of stoppage, it is seen that extractor is not quite up, no attempt should be made to raise it. It should be first pushed down before the crank handle is turned over to the front, as by this means all risk of firing a cartridge accidentally is avoided.

2. When a temporary stoppage necessitates the employment of the spare lock, feed block, etc., the part which has been removed should be repaired as soon as possible, making it again available as a reserve.

3. Should it ever be necessary to release the lock spring, with the lock out of gear, this should be done with the extractor fully up, and firing pin hole opposite firing pin.

4. As the clearing of a stoppage often knocks the sights off the aiming mark, care should be taken that the gun is immediately relaid.

TABLE OF STOPPAGES.
I.	II.	III.	IV.
Position of crank handle and its indication.	Immediate action.	Probable cause.	Prevention of recurrence.
FIRST	(i) Turn the crank handle on to the buffer spring, pull the belt to the left front, and let go the crank handle.	The extractor has not dropped. This may be due to:—
Indication. The lock is unable to come back far enough to allow the extractor to drop.		(a) Too heavy fusee spring.
	(ii) If failure recurs, lighten fusee spring by three “turns.”	(b) Excessive friction, due to want of oil; grit or tight pockets in the belt, or excessive packing in cannelure or packing gland.	(b) Clean and oil working parts. Examine the belt, which should be dried if damp; or if the stoppage is due to a new or stiff belt, the pockets should be plugged. If due to excessive packing, examine and repack cannelure or packing gland.
		(c) Partial loss of the force of the explosion due to—
		(i) Worn barrel.
		(ii) Defective ammunition.	(c) (i) The barrel should be examined at the first opportunity, and if much worn in the lead should be changed.
SECOND.	(i) Force the crank handle on to the buffer spring. Open the cover and examine the cartridge on the face of the extractor. If a damaged cartridge, or an undamaged cartridge with the front portion of a separated case adhering to it, clear the face of the extractor and re-load.	(i) (a) Damaged cartridge. The cartridge is unable to enter the chamber completely, although it has commenced to do so.
Indication. The lock is unable to go fully home after recoil.		(b) Separated case with front portion adhering to undamaged cartridge.
	(ii) If an undamaged cartridge with no front portion of separated case adhering to it is found on the face of the extractor, clear the face of the extractor and replace the lock, keeping the crank handle on the buffer spring. Take the clearing plug (seeing that the centre pin is back) and insert it into the chamber. Push the pin well home by allowing the lock to go forward. Then keeping a firm pressure on the crank handle, give the clearing plug a rocking motion; withdraw the lock; lever back the handle of the clearing plug, withdraw it (seeing that the front portion of the separated case is on the clearing plug) and re-load.	(ii) Separated case. The front portion of the case causes an obstruction and prevents the next cartridge from going into the chamber.	(b) If a succession of separated cases occur the connecting rod must be lengthened. (See para. 82.)
THIRD.
Indication. The extractor is unable to rise to its highest position. If the feed block slide is jammed, there is a fault in feed.	(i) Strike the crank handle on to check lever by a glancing blow with the palm of the hand. If failure recurs, strengthen the fusee spring by three turns.	(i) (a) Too light fusee spring.	(i) (b) Clean and oil working parts.
		(b) Excessive friction.
	Note.—If the continued strengthening of the fusee spring results in the crank handle stopping in the first position, change the lock, putting the fusee spring back to normal; if failure recurs take muzzle attachment into use. (See para. 44.)
	(ii) If (i) fails, slightly raise the crank handle, pull the belt to the left front, let go the crank handle, and then strike it down on the check lever.	(ii) A cartridge is fed up slightly crossways, or a long brass strip is bent.	(ii) Carefully examine the belt.
	(iii) A. If (i) and (ii) fail, examine feed block slide. If jammed, No. 1 holds up the crank handle and opens the cover. No. 2, with the assistance of No. 1, removes the feed block, and replaces it by the spare one. Meanwhile No. 1 forces down the horns of the extractor, and places the crank handle on the buffer spring. As soon as the spare feed block is in position, No. 1 closes the cover and pulls the top cartridge of a fresh belt into position and lets go the crank handle.	(iii) A. (1) Badly filled belt, or a belt with worn or loose pockets. The cartridges projecting unevenly from the belt prevent it entering or passing freely through the feed block.	(iii) A. (1) Carefully examine the new belt.
		(iii) A. (2) Belt box not being in line with the feed block; the belt does not lead up correctly to the feed block and becomes jammed.	(iii) A. (2) See that the new belt box is in line.
		Note.—The effect of a fault in feed is that the top pawls, being engaged behind a cartridge in the belt, are held fast when some obstruction, such as above, prevents the belt from passing freely through the feed block. The recoiling portions, being connected by the top and bottom levers to the slide, are arrested and prevented from going home. The distance they are held back depends upon the point at which the obstruction asserts itself.
	(iii) B. If free, No. 1 opens the cover. No. 2 forces down the horns of the extractor. No. 1 clears the face of the extractor, and changes the lock. He removes the cartridge in positioning the feed block and re-loads.	(iii) B. (1) Damaged cartridge grooves.
		(2) Broken gib spring.
		(3) Broken gib. In these cases the extractor is prevented from rising to its highest position. It may be necessary sometimes to slide the cartridge or the empty case upwards, when clearing the face of the extractor.
		(4) Thick-rimmed cartridge.
		Note.—If it is apparent that the stoppage is due to a thick-rimmed cartridge, it will not be necessary to change the lock.
FOURTH.	(a) Turn the crank handle on to the buffer spring, pull the belt to the left front, and let go the crank handle.	(a) (1) No cartridge in the chamber.
Indication. That there has been no explosion, or, if any, that there has been little or no recoil, the lock remaining in its forward position.		(2) Defective ammunition.
	(b) If (a) fails, place the crank handle on to the buffer spring twice, change the lock, and re-load.	(b) (1) Broken or damaged firing pin.
		(2) Broken lock spring.