1951: Chapter 4 – Spare Parts and Repairs




1. To teach the names and use of various spare parts carried so that, should a part of the gun be broken or damaged, a spare part can be obtained with the minimum of delay.

2. To teach the correct method of packing spare parts.

Class and instructors

3. Squads under squad instructors. Squads seated round a table.


4. Gun and tripod, spare parts case and box.


5. One 45-minute period.


6. Mount the gun near the table so that everyone can see. Check the contents of the spare parts case and box.


7. State the aim of the lesson (see paras 1 and 2). Explain that generally speaking the parts that are most frequently required are in the spare parts case. There is one spare parts case for each gun. The spare parts box, of which there is one to each section, contains a reserve of spare parts and certain additional spares which are not so frequently required.

Spare parts case

8. Put all the contents of the spare parts case on the table.

9. Name each of the parts in the spare parts case and state the number carried, and order various members of the squad to pick up the parts from the table.

10. The following are the contents of the spare parts case:–

Balance, Spring 1
Can, Oil 1
Extractors 2
Lock, Breech 1
Plug, Clearing 1
Spring, Fusee 1
Wallet 1
Tool, Combination 1


11. Name each of the parts contained in the wallet, and state the number carried. Ask various members of the squad to pick up the parts from the table and indicate where they would go on the gun.

12. The following are the contents of the wallet:–


Bottles, Oil, Mk. 4 or 5 1
Cork for plug 1
Cup, Muzzle attachment 1
Disc, Muzzle attachment 1
Fusee, with chain 1
Levers, Bottom 1
Levers, Top 1
Packing, Asbestos 1
Pins, Split, Lever feed block 1
Pins, Trigger lock 1
Pins, Tumbler 1
Pins, Firing 2
Pins, Keep split, 1/8 X 2½ inches (for Mark 4 tripod mounting) 3
Pliers, side cutting, pairs 1
Protector, muzzle 1
Pull-through, double 1
Punches, No. 3 1
Punches, No. 5 1
Screwdrivers, small 1
Sear, with spring 1
Springs, lock 2
Trigger 1
Tumbler 1
Washer, adjusting No. 1, .003-inch 3
Washer, adjusting No. 2, .005-inch 3
Wire gauze (pieces) 2
Washers, leather 1

13. Show how to pack the contents of the spare parts case. All the contents of the wallet go into the rear pocket of the wallet with the exception of the screwdriver and pliers which fit into the front pocket. The wallet is then fastened with its strap and pushed into the case. The oil can can then be pushed down in front of the wallet and the clearing plug, combination tool and the fusee spring stood on end alongside the oil can. The extractors can then be placed in, and the balance spring pushed into a fold of the wallet. Finally the lock can be placed flat on its side on top and the case fastened with its strap.

Spare parts box

14. Put all the contents of the spare parts box on the table.

15. Name each of the parts contained in the spare parts box, and state the number carried. Detail one of the squad to pick the parts from the table and indicate where they would go on the gun or what tools would be used for various operations.

16. The following are the contents of the spare parts box:–

Blocks, Feed, RH 2
Boxes, Patch, First – Aid, complete 1
Boxes, Small Parts 1
Brushes, Oil, MG 1
Bush, Axis, Side levers 1
Chains, Crosshead joint 1
Collars, Roller 1
Cork for plug 2
Cups, Muzzle attachment 1
Discs, Muzzle attachment 4
Fusee, with chain 1
Gib 1
Hammer 1
Lever, Extractor, Left 1
Lever, Extractor, Right 1
Packing, Asbestos (5-Yard pieces) 8
Pins, Crosshead joint 1
Pins, Elevating joint 1
Pins, Split, Keeper, 1/16-in X 1-in 3
Pins, Trigger lock 1
Pins, Tumbler 1
Pins, Firing 4
Pins, Split, Collar, Roller 2
Pins, Keep split, 1/8 X 2½ inches (for Mark 4 tripod mounting) 6
Pins, Split bush, Axis, Side lever 1
Pins, Muzzle attachment 1
Pins, T fixing, rear crosspiece 1
Plugs, Cork, Complete 1
Plugs, Screwed 1
Plugs, Front Cover Catch 1
Plungers, Front Cover Catch 1
Roller 1
Screws, Clamp, Checking traverse 1
Sights, Fore 1
Sights, Tangent 1
Spanner, Adjustable 1
Springs, Bottom pawl 2
Springs, Rear cover lock 4
Springs, Front cover catch 2
Springs, Gib 2
Springs, Lock 8
Springs, Safety catch with piston 4
Springs, Sear 2
Springs, Shutter catch 2
Springs, Tangent sight 1
Springs, Top pawls feed block 4
Springs, Trigger bar 4
Washers, Adjusting, No. 1 4
Washers, Adjusting, No. 2 4
Washers, Elevating Nut (Tripod Mk. 4) 6
Wire Gauze (pieces) 8

17. Show how to pack the contents of the spare parts box. The feedblocks, hammer, tangent sight, adjustable spanner, muzzle cup and discs fit into their respective brackets in the box. All the small spare parts, pins, springs, etc, go into the small tin, which fits in the slots on the side of the box, and the reminder of the spares loose in the box.

18. Practice the squad in packing the spare parts case and box.


19. Various competitions on spare parts can be held to stimulate interest. One of these is described below:–

20. One spare parts competition can be based on the game “House.” The instructor should prepare “House” cards beforehand with the names of spare parts in the squares instead of numbers. Each card should be different. One card is given to each member of the squad. The instructor then holds up various spare parts in turn, without naming them, and if the spare part is listed on the card the members of the squad tick them off. The game proceeds unti lone card is completed as in “House.” The game can be mae more difficult by the instructor requiring the squad to note on the card the number of the various spares carried and where they can be found.


21. Questions from the class.

22. Questions to the class. Specimen questions:–

(a) How many lock springs are carried, and where are they carried?

(b) The sear spring has broken on your gun. Where can you find a spare?

(c) The spare sear spring breaks. What action do you take now?

23. Sum up progress made.

Lesson 18. – REPAIRS



1. To teach the soldier how to fit spare discs to the muzzle attachment.

2. To teach the soldier how to repair damage to the barrel casing.

3. To teach officers and NCOs the method of dealed with a damaged or displaced foresight.

Class and instructors

4. Squads under squad instructors. Squads seated in semi-circle around the guns.


5. This lesson will not take a full period for private soldiers.

6. For officers and NCOs – one 45-minute period.


7. Gun, tripod, spare parts case and boxes, patch, first aid.

8. When lateral adjustment of the foresight is taught, a portable blackboard will be required.


9. State the aim of the lesson (see paras 1 and 2).

NB – The lateral adjustment of the foresight may only be carried out by experienced officers and NCOs and will not be taught to private soldiers.

Fitting spare discs to the muzzle attachment

10. Tell the squad the metal discs wear out and are liable to damage.

11. Explain and demonstrate the method of replacing metal discs. The front cone is unscrewed and the edge of the disc is cut pushing up sufficient metal to form a hold for the pliers. The disc is then removed with the pliers and replaced with a new one. In replacing the disc, it may be necessary to tap it on to the front cone.

12. The squad cannot be practised in this art as it will entail damage to the discs.

Perforation of the barrel casing

13. Tell the squad that should the barrel casing be pierced by bullets or other means, the gun will be put out of action. Semi-permanent repairs will be carried out by an armourer at the first opportunity, but to enable the gun to be in action again with the least possible delay, temporary “first aid” can be carried out by the gun team.

14. Explain and demonstrate how to repair an imaginary hole in the barrel casing. A rubber pad from the tin box in the spare parts box is forced over the hole. The metal plate is positioned on top of this and the whole fixed firmly to the barrel casing by means of the flexible clips provided.

15. State that a hole in the front cap of the barrel casing cannot be repaired in this manner, but a fairly water-tight repair can sometimes be effected by hammering in a wooden plug.

16. Practice the squad in carrying out first aid on the barrel casing.

Lateral adjustment of the foresight

17. Tell the squad that if the foresight has been damaged or displaced, lateral re-adjustment will be necessary. This will be carried out on the 30-yards range.

18. State that a target is required with a thick vertical line as an aiming mark and a thin pencilled line 5/8-inches to the right of the centre of the thick line. Draw this on the blackboard and set it at a suitable distance from the gun.

19. Say that the socket of the tripod must be perfectly upright and settling-in bursts fired into the stop butts. To avoid error caused by holding, the gun is punch fired, the belt being spaced in 10-round groups.

20. Demonstrate and teach punch firing. The gun is half-loaded and, with the thumb-piece pressed, a punch is inserted between the safety catch and the firing lever. The gun is then laid accurately on the thick line. If the crank handle is now pulled back, the belt pulled and the crank handle released the gun will fire a burst of 10 rounds. The aim is now re-checked to see that the tripod has not moved. The punch is removed and the gun is unloaded and cleared.

21. Show on the blackboard that is the gun is correctly sighted, the MPI will fall on the thin pencilled line.

22. Demonstrate that if there is any error, the foresight is tapped in the same direction as the error, using a hammer and a No. 3 punch.

23. State that another burst of 10 rounds will be fired after each adjustment until sighting is correct. Adjustments are very fine and great care must be exercised in tapping the foresight. When the foresight is very tight, the bracket must be supported to prevent it being jarred loose.

24. Practice the squad by marking imaginary MPIs on the blackboard and having the squad adjust the foresight accordingly.


25. Questions to and from the squad.

26. Further practice if necessary.

27. Sum up main points.

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