Chapter I: Front Matter (1)

Machine Gun Manual

By CAPTAIN H. DOUGLAS
Sherwood Foresters
National Team (England)
Kolapore Team (Great Britain)
British Rifle Team (Australian Tour)

A COMPLETE MANUAL TO MACHINE GUNNERY
containing details of
MAXIM VICKERS LEWIS COLT HOTCHKISS
together with
DRILL
(Elementary and Advanced)
Fire Orders, Notes from the Front
and a mass of other
Useful Information

ILLUSTRATED

LONDON
HARRISON AND SONS
Printers in Ordinary to His Majesty Military Printers, Publishers and
Stationers
ST. MARTIN’S LANE, W.C.

_Telephone 11596 CENTRAL_

MAXIMS Makers of Good Clothes

_Telephone 990 MAYFAIR_

]

For the best value in

MILITARY OUTFITS.

THE “MAXIM” Trench Coat (as illustrated) with _detachable fleece lining_. Made from fine quality Khaki Twill, lined with rainproof lining and interlined with oiled silk,

£4 . 10 . 0

Light and warm, absolutely wind and rain proof.

Write for complete illustrated list.

71, NEW BOND STREET, W. 141 & 142, FENCHURCH STREET, E.C. LONDON.

Contents.

Maxim Gun. PAGE
General description 5
Plates and list of parts 11
To mount and dismount 16
„ load and unload 16
„ clean 17
Muzzle attachment 18
Fusee spring 18
Stripping and assembling 19
Examination and testing 21
Stoppages 23

Vickers’ Light Gun.
Plates and list of parts 31
Special features 35
To mount and dismount 36
„ load and unload 36
„ clean 36
Muzzle attachment 37
Fusee spring 37
Stripping and assembling 38
Stoppages 39
Examination and testing 39
Points to be attended to (Maxim and Vickers’) 40
Belt filling 40

Lewis Automatic Gun.
Plates and list of parts 43
Description 47
To load and unload 49
Stripping and assembling 50
Stoppages 53

Colt Automatic Gun.
Description 55
To load and unload 58
Stoppages 59
Stripping and assembling 62
Plates and list of parts 65

Hotchkiss Portable Machine Gun.
Component parts and plates 67
General description 71
Action of the mechanism 71
To strip and assemble the gun 73
Points to be attended to before firing 78
Rapid change of barrel in the field 80
Stoppages 82
Cleaning and care 83
Feed strip filling machine 83

General.
Duties 85
Section drill (with and without transport) 86
Elementary tests 90
Machine gun characteristics 90
Fire direction 91
Fire orders 93
Signals 94
War establishment 95
General machine gun course 97
Notes from overseas 100
Points to remember 100
Choice of gun position 100
Employment of machine guns 100
Occupation of positions 102
Trench work 106
In action 107
Village fighting 109
Attack on entrenched position 110
Co-operation 112, 118
Targets and ranges 112
Guns brigaded in action 115
Indication and recognition 116
Observation of fire 117
Ammunition supply 119
Mechanical troubles 119
Pack transport 120
Training in billets 121
Painting of guns 122

_Telephone 11596 CENTRAL_

MAXIMS

Makers of Good Clothes

_Telephone 990 MAYFAIR_

FOR THE BEST VALUE IN
MILITARY OUTFITS

Service Kit for any regiment in 36 hours.

£ s.
Service Tunic 3 3
Slacks 1 1
Bedford Cord Breeches 2 2
British Warm (fleece lined). 3 3
Sam Browne Belt (complete) 2 2

_Complete! Illustrated List on request, or better still, call and
inspect our stock._

141 & 142, FENCHURCH STREET, E.C.
71, NEW BOND STREET, W.
LONDON.

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The Maxim Gun.

GENERAL DESCRIPTION.

Weight of the ·303-in. gun, 60 lbs. Weight of the tripod, 48 lbs. Weight of ammunition box containing one filled belt, Mark VI 21 lbs., Mark VII 19½ lbs.

The gun may be considered as divided into two portions—the non-recoiling and the recoiling. It is worked automatically by two forces—the explosion of the charge which forces the recoiling portion backwards, and a strong spring (called the fusee spring) which carries it forward.

Non-Recoiling Portion.

The non-recoiling portion consists of the barrel casing and breech casing, and is attached to the mounting by the crosshead and elevating joint pins.

The barrel casing is of gunmetal, holding about seven pints of water to keep the barrel cool when firing; it has three openings, one on the upper right side near the breech for filling, one underneath near the muzzle for drawing off the water, and the third (also near the muzzle) for allowing the steam, but not the water, to escape. The first two are closed with screwed plugs; the last is open and connected with the steam tube, and carries the condenser nipple.

A cork plug is provided which can be inserted in the steam escape hole when the gun is travelling, in order to prevent waste of water from jolting. The plug should always be taken out before commencing to fire, and put in again before the gun changes position, unless the condenser is attached to the barrel casing and can be conveniently moved with the gun.

To prevent the escape of water, there is at the forward end of the barrel casing asbestos packing, which is held in position round the barrel by the packing gland. At the rear end of the barrel there is a cannelure, also filled with asbestos packing, which prevents the escape of water when the gun is working, and a gunmetal valve immediately in front of the barrel block, which prevents the escape of water when the gun is not firing and the barrel home.

The steam tube consists of a fixed tube and an outer tube, termed the slide valve, so arranged as to slide freely along the fixed tube. In the fixed tube there is a hole near each end, and a third hole in the threaded portion in front, to connect with the steam escape hole which is bored in the solid part of the front end of the barrel casing. This tube is fixed into the solid end of the barrel casing, and is retained in position by a screw which, being kept in adjustment by a keeper screw, ensures that the third hole coincides with the steam escape hole. At the breech end it fits into a recess.

If the gun is fired with elevation, the valve slides backwards, and, closing up the hole at the rear end of the tube, prevents the water entering; at the same time it leaves the front hole uncovered, which, being above the water level, allows the steam to enter the tube and escape through the steam escape hole in the barrel casing. Similarly, if the gun is fired with depression, the valve slides forward and allows the steam, but not the water, to escape through the rear hole.

In the lower part of the barrel casing is the ejector tube through which the empty cartridge cases are ejected from the gun. The tube is fitted with a spring, which prevents the cases falling backwards into the gun.

The breech casing consists of two outside plates, a bottom plate which is riveted to them, and the rear cross piece, the whole being closed by a cover.

The outside plates are dovetailed into the barrel casing, and, together with the cover, are secured by means of a cover joint pin.

On the outside of the right hand plate there are the following fittings:—(1) a socket and stud for securing and supporting the buffer spring; (2) the resistance piece, and (3) the stud for the check lever. On the outside of the left hand plate are three studs for holding the fusee spring box, the rear one being on the slide mentioned below; there are also two other studs on this plate for fixing a shoulder piece to the gun if required. In both plates are slots partly closed by slides, in which the crank bearings move, and on the inside of both plates are solid cams which control the path of the extractor. Below these, and supporting the side plates, are rests, along which the recoiling portion travels.

Along the bottom plate lies the trigger bar, and underneath is a bracket to which the elevating gear is attached by means of the elevating joint pin.

The outside plates are connected at the rear end by the rear cross piece, into which they both dovetail; this piece is fitted with (1) hollow handles, which are also used for carrying oil, and are closed by milled heads, fitted with camel-hair brushes; (2) a firing lever and spring, the lower end of which fits into the trigger bar, while the upper end is provided with a double button for firing; (3) an automatic double-handed safety catch, which is so arranged that unless it is held up the firing lever cannot be pressed forward; and (4) a pivoted shutter, which, when moved to the right or left, uncovers an aperture through which (when the lock is removed and the crank handle vertical) the barrel can be inspected or cleaned from the rear.

The cover is fitted with (1) springs to ensure the extractor dropping on recoil; (2) a gunmetal block to keep the lock down when back, and (3) at the rear end, a lock to fasten it. On the upper surface is the tangent sight, consisting of a stem, a graduated plate and slide. Running through the centre of the slide is a pinion, the teeth of which work in the rack on the stem. A pawl is secured to the pinion by a fixing pin. On the under side of one end of the pawl are teeth, which engage in the circular rack on the slide.

When the slide is at rest the stud on the inside of the milled head (nearest the slot for the slide spring) bears on the stud on the pawl immediately over the teeth, being actuated by the slide spring, thus forcing the teeth into the circular rack. This keeps the slide stationary on the stem. On rotating the milled head, this stud is partly disengaged from the stud on the pawl, thus permitting a second stud on the milled head to press on one side of the V-shaped ramp at the other end of the pawl. This action releases the teeth sufficiently to permit the pawl being moved round the circular rack by the action of the stud bearing on one side of the V-shaped ramp on the pawl; this moves the slide along the stem. On releasing the milled head, the spring positions the cover, thus causing the stud on the pawl to become once more engaged with the stud on the milled head and force the teeth into the rack.

Recoiling Portion.

The recoiling portion (which is mounted inside the non-recoiling portion) consists of a barrel and two side plates which carry the lock and the crank.

The barrel is coated with copper to protect it from rust; the gunmetal valve referred to above, which prevents the escape of water to the rear, is fitted just in front of the breech end, which is formed in the shape of a block; this block has two studs, one on each side, called the barrel trunnions, by means of which the barrel is attached to the side plates.

The side plates are each provided with a hole to receive the barrel trunnions, and in the case of the ·303-in. gun, with hooks for engaging the recesses on the top of the barrel block; also guides in which the flanges of the lock move, which are enlarged at the rear end to act as crank stops; in addition each has a bearing, through which the crank passes, thus connecting the latter with the barrel; these bearings move in slots in the breech casing. The left side plate is fitted with a connecting rod spring to hold the connecting rod upright when the lock is removed, and the right side plate is fitted with a side plate spring near the barrel, to keep the extractor in its highest position when the lock is home. The left side plate is prolonged to the front, and has a recess in which the bottom lever of the feed block engages.

The crank is fitted with a connecting rod, which is free to rotate on the crank pin, and, outside the breech casing on the right, with a handle which has a curved projecting arm, and on the left with a fusee, to which is attached a chain.

The connecting rod is attached to the crank by means of an axis pin, called the crank pin, and is arranged to take the lock by means of an interrupted screw, thereby connecting the crank and the lock. The connecting rod is divided into two parts, enabling its length to be increased by inserting washers of varying thicknesses. By this means it is ensured that a firm pressure is kept on the base of the cartridge at the moment of firing, thus preventing separations.

On the left of the breech casing there is a strong spiral spring, called the fusee spring, the rear end of which is connected by the fusee chain and fusee with the crank; the front end is attached to the breech casing by means of the fusee spring box and adjusting screw, which passes through the front end of the fusee spring box, and through the nut at the front end of the spring.

The lock is attached to the connecting rod by the screwed head, and when in the firing position closes the breech. In this position it is held by the side levers, the crank (which bears against stops on the side plates), and the connecting rod, the joint being slightly above the horizontal, to prevent the breech being opened at the moment of firing. The lock has a reciprocating motion communicated to it by the rotation of the crank, and is kept in position during its backward and forward movements by means of flanges working in guides on the side plates, and, when at the end of its backward travel and clear of the guides, by the gunmetal block underneath the cover.

The extractor is moved upwards by means of the side and extractor levers, and when in its highest position, is retained there by means of the side plate spring; this ensures the hole for the firing pin being opposite the centre of the base of the cartridge when the lock is home. The upward and downward movements of the extractor are regulated by guide ribs and stops; the upper stop forms part of the lock casing, and the lower one is removable.

The feed block, which fits under the cover into a recess cut in the breech casing, is provided with a slide to which are attached two pawls with springs, for the purpose of moving the cartridges from right to left; the slide has a transverse motion given to it by means of two levers which are fitted together; the top lever has a slot which engages a stud on the slide, and on the bottom lever is a stud which engages in a recess in the left side plate; by this means the slide is connected with the recoiling portion. The feed block has also two stationary pawls, which engage under the belt and prevent it slipping backwards during firing. To facilitate the entrance of the cartridges, the feed block is provided with a band roller, and in addition has steel guides fitted above and below in the cartridge way, which ensure the cartridges coming to the exact position where they can be gripped by the extractor; they are prevented from being pushed too far through to the left by means of the cartridge and bullet stops, which are inside the feed block.

The gun is supplied with cartridges from a belt which passes from right to left through the feed block. This belt is formed by two pieces of webbing connected together by eyelets and brass strips of two lengths, the projecting strips showing how far the cartridges should be inserted; the belt is made thick at the edge next the bullets by being folded over a piece of cord, so that the cartridges may be kept parallel in passing through the feed block, and lie evenly in the ammunition belt boxes.

(Flexible steel belts are now being used. These fold into their box in sections, and by withdrawing a pin the unexpended portion can be detached and packed away immediately. They appear to be giving considerable satisfaction, inasmuch as “belt troubles” are practically impossible.)

Converted Guns.

Converted guns are the original ·45-in. guns made to take the ·303-in. cartridge.

The conversion consists in the substitution of ·303-in. barrels for the ·45-in. barrels and the adaption of the mechanism to the smaller calibre by the introduction of new parts or the alteration of existing parts.

The Mark II differs from the Mark I in being fitted with the service ·303-in. barrel and muzzle attachment for ball firing, whereas the Mark I has a special muzzle attachment and a heavy barrel. The difference in the barrels affects also certain other parts. In both Marks I and II converted guns the attachment for ball firing must always be on the guns, as, owing to the greater weight of the component parts, these guns will not work without it.

The tangent sight is graduated to 2,500 yards.

The weight is 64 lbs.

In other respects they resemble the ·303-in. gun except that the connecting rod is not above the horizontal and that there is a space of about ⅒ of an inch between the projecting arm of the crank handle and the resistance piece.

Ammunition.

All marks of ·303-in. ball ammunition may be used, but care should be taken to select ammunition of the most recent manufacture. Mark VII can, however, be used only in guns specially modified to take it.

Explanation of Plates I and II.

1. End of crank.

2. Projecting arm of crank handle.

3. Crank handle.

4. Breech casing.

5. Fusee spring }
}
6. Chain } Dotted
} lines in
7. Fusee } Fig. 1.
}
8. Spring box }

9. Resistance piece.

10. Buffer spring.

11. Check lever.

12. Lock casing.

13. Firing lever.

14. Trigger bar.

15. Projection on trigger bar.

16. Trigger.

17. Tumbler.

18. Lockspring.

19. Firing pin.

20. Crank.

21. Crank pin.

22. Connecting rod.

22A. Cotter.

23. Side levers.

24. Sear.

25. Extractor.

26. Barrel.

27. Ejector tube.

28. Horns of extractor.

29. Keeper bracket.

30. Side cams.

31. Cover spring.

32. Cover.

33. Gib.

34. Adjusting screw for fusee spring.

35. Extractor spring.

36. Handles.

37. Double button.

38. Trigger bar spring.

39. Gib spring.

41. Extractor levers.

42. Belt.

43. Upper extractor stop.

44. Groove for side plate spring.

45. Cartridge grooves.

46. Ejector tube spring.

47. Side plates.

48. Guides in which flanges of lock move.

49. Guide ribs for extractor.

50. Cover lock.

51. Gunmetal block.

52. Hole for firing pin.

53. Safety catch.

54. Screwed head.

55. Connecting rod spring.

56. Crank bearings.

57. Slots, breech casing.

58. Crank stops.

59. Ammunition belt box, No. 2.

60. Feed block.

61. Top lever feed block.

62. Cork plug.

63. Feed block slide.

64. Top pawl.

65. Bottom pawl.

66. Band roller.

67. Barrel casing.

68. Screwed plug for filling.

69. Asbestos packing.

70. Packing gland.

71. Cannelure for asbestos packing.

72. Gunmetal valve.

73. Steam tube.

74. }
} Holes in steam tube.
75. }

76. Slide valve.

77. Steam escape hole.

78. Milled heads of oil brushes.

79. Oil brush.

80. Sight, tangent.

81. Sight, fore.

82. Shutter.

83. Shutter spring.

84. Shutter catch.

85. Notch for shutter catch.

86. Screwed plug for emptying.

87. Slides, right and left.

88. Gib spring cover.

89. Check lever collar.

90. Cover lock spring.

91. Safety catch spring.

92. Tangent sight spring.

93. Bottom lever feed block.

94. Trunnions of barrel.

95. Extractor stop.

96. Firing lever spring.

97. Shutter pivot screw.

Plate I.

GUN MAXIM, ·303 INCH.

SIDE ELEVATION.
]

Plate II.

GUN MAXIM ·303 INCH.

PLAN WITH COVER REMOVED.
]

MOUNTING, TRIPOD, ·303-in. MAXIM GUN, MARK IV.

The mounting consists of a crosshead (_a_), elevating gear (_b_), and socket (_c_), mounted on three legs.

It is constructed to give 13 degrees elevation and 25 degrees depression at heights varying from 14½-in. to 30-in. from the axis of the gun to the ground. By arranging the position of the rear and front legs respectively, elevation may be given up to about 43 degrees and depression to 55 degrees. An all-round traverse can be obtained.

The crosshead (_a_), to which the gun is pivoted, is formed with a pivot to fit into the socket (_c_) and an arm (_d_) which carries the elevating gear (_b_).

The elevating gear, which is actuated by a hand wheel (_v_), consists of an inner and outer screw (right and left-handed) and a nut working within a tumbler (_g_). The tumbler is split and provided with a jamming bolt (_h_), by which the wear may be taken up. The inner part of the screw is attached to the crosshead by a chain. Chains also, for future manufacture and replacement, will secure the joint pins to the mounting.

The socket (_c_) is bored to receive the crosshead and is provided with three lugs (_n_), to which the legs are hinged; a jamming block and screw with handle (_f_) is attached to the front to secure the crosshead in any desired angle of traverse; the block works in a recess in the upper portion of the crosshead and prevents it from rising. Both faces of the rear lug and one face of each front lug are fitted with clutch plates having radial serrations to correspond with similar serrations on the faces of the leg joints. Joint studs with disc spring and jamming handle (_s_) are

Plate III.

MOUNTING TRIPOD ·303 INCH, MAXIM GUN MARK.

SCALE = ⅛

SIDE ELEVATION.
]

_A_ _Crosshead_

_B_ _Elevating gear_

_C_ _Socket_

_D_ _Arm, crosshead_

_F_ _Screw, clamp checking traverse_

_G_ _Tumbler, elevating gear_

_H_ _Bolt, jamming elevating gear_

_J_ _Front legs_

_K_ _Rear leg_

_M_ _Shoes_

_N_ _Socket lugs_

_S_ _Stud, joints, a jamming handle, front legs_

_T_ _Joint pin, a jamming handle rear leg_

_V_ _Handwheel elevating gear_

fixed to the front lugs, by which the legs are securely clamped to the socket in the required position.

The legs (_j_, _k_) are of tubular steel, the lower ends being fitted with shoes (_m_) to steady the mounting on the ground, and the upper ends having a joint with radial serrations mentioned above. The rear leg is provided with a joint pin with nut and jamming handle (_t_).

On a portion of the periphery of the leg joints, numbers are stamped at regular intervals so that when read in conjunction with a zero mark the relative position of the legs to their normal position may be readily seen.

A strap is fixed to the rear leg to secure the three legs during transport.

When firing, the ammunition box is placed on the ground on the right side of the gun.

Weight of mounting 48 lbs. variable.

TO MOUNT AND DISMOUNT GUN.

To Mount Gun.

Machine gunner No. 1 will carry tripod into position, elevating screws being equally exposed. Cross head upright. Legs clamped tight.

No. 2 will carry gun to right side of tripod, holding rear cross piece with left hand, gun muzzle to rear under right arm. Kneel on left knee, facing tripod, and supporting weight of gun on right knee, place it on tripod, pushing in and turning down the crosshead joint pin. Remove cork plug finally from steam escape hole, No. 1 fixing elevating joint pin.

To Dismount Gun.

No. 1 removes crosshead and elevating joint pins, No. 2 replaces cork plug and removes gun as in mounting, carrying it to its original position in rear, No. 1 following with the tripod. Joint pins will then be pushed home and turned down, legs folded and clamped.

TO LOAD AND UNLOAD GUN.

To Load.

Pass the tag of belt through feed block from right side, turning crank handle with right hand on to buffer spring, and pull belt through with left hand to left front as far as it will go, let go crank handle, the first cartridge will then be gripped by the extractor.

Again turn crank handle on to buffer spring, and pull belt to left front, letting go crank handle—the gun is then ready for firing.

Make each motion clear and distinct.

On pressing double button the gun will fire automatically until pressure is released.

To Unload.

Turn crank handle twice in succession on to buffer spring, letting it fly back to the check lever each time. Press up the bottom pawls and remove belt from feed block, then release the lock spring by pressing double button.

TO CLEAN GUN.

Mechanism.

Equal parts of G.S. lubricating oil and paraffin should be used, each part being thoroughly dried and slightly oiled with G.S. lubricating oil.

The various parts can easily be got at by “hanging” the lock as follows:—

Turn the crank handle on to buffer spring, raise lock slightly till clear of guides, allow handle to come back a little, and lock to rest on top of guides, when it will be fixed and easily accessible.

Barrel.

Turn crank handle over against buffer spring, open cover, raise lock, and as the crank handle is allowed to come slowly back raise it and let it rest upon the top of the rear crosspiece.

The cleaning rod may then be used from muzzle of barrel.

Daily cleaning is absolutely necessary for at least ten days after using ball ammunition and the bore should at all times be left coated with oil.

(A double-ended pull through may be used to remove hard fouling.)

Treatment in Frosty Weather.

In frosty weather, when water is kept in the barrel casing, a blanket or some other thick covering should be kept wrapped round the barrel casing to prevent the water freezing. The working parts of the gun should only be slightly oiled with a lightly-oiled rag. In climates where the temperature is likely to fall much below freezing point, not more than about 5 pints of water should be put into the barrel casing (25 per cent. of glycerine mixed with the water will prevent it from freezing so quickly).

MUZZLE ATTACHMENT.

The force of recoil is increased by the use of the muzzle attachment. Defects in the working of the gun are overcome by this means.

It consists of a steel cylinder with a hole bored longitudinally through it, the front end of cylinder being partially closed by a screw. Gases escaping from the muzzle of barrel are partially confined to the interior of attachment, the pressure of the gas acting on the muzzle of barrel giving additional recoil.

It is fitted by unscrewing the packing gland from the barrel casing, and screwing the attachment into the packing gland by means of the steam tube and packing gland key.

The attachment should be removed from the gun and cleaned immediately after firing, all metallic fouling being carefully scraped away.

THE FUSEE SPRING.

On the left of the breech casing, the rear end being connected by the fusee chain and fusee with the crank, the front end is attached to breech casing by means of fusee spring box and adjusting screw which passes through front end of fusee spring box and through the nut at front end of spring.

To Weigh and Adjust.

Cock the lock, place loop of spring balance over knob of crank handle and pull vertically upwards, resting wrist on breech casing, the reading indicated when crank handle commences to move will be the weight of the fusee spring. This should be between 5 and 7 lbs. (for converted Mark I Guns between 10 and 12 lbs.).

If spring is over, or not up to weight, remove fusee spring box and adjust by means of adjusting screw, six turns making a difference of about 1 lb. (Turning screw clockwise increases weight and vice versa.)

The tension should always be kept as high as possible, consistent with maintaining the normal rate of fire (500 rounds per minute).

STRIPPING THE GUN.

The gun is stripped in the following order:—

NOTE.—All pins are driven in from right to left, and out in the reverse direction.

(i) =Lock and Feed Block.=

Raise the cover, turn the crank handle on to the buffer spring, see that the extractor drops, place finger between the extractor and stop, raise the lock and allow the crank handle to come slowly back on to the check lever; slide the live cartridges out of the extractor, keeping the latter down. Give the lock ⅛ turn to the left and lift off. Lift the feed block out.

(ii) =Fusee Spring Box.=

With the right hand at the rear and the left hand at the front, press the box forward until clear of the lugs, and remove. Disconnect the fusee chain and remove the box and the spring. Care should be taken to throw no cross strain on the chain.

(iii) =Tangent Sight and Cover Lock.=

Lower the cover, putting a screwdriver across the breech casing under the gunmetal block, drive out the axis pin of the stem and remove with its piston and spring. Close the cover, press in the cover lock, and, with the large screwdriver, remove the stop screw; the lock with its piston and spring can then be removed.

(iv) =Cover.=

Drive out the fixing pin of the cover joint pin, remove the collar and joint pin and take off the cover.

(v) =Rear Crosspiece.=

Drive out the tapered fixing pin, grasp with the left hand the left handle of the rear crosspiece, slightly raise the casing and, with the mallet, strike the top edges of the casing alternately until the rear crosspiece is clear of the dovetails on the casing. Lift out the trigger bar.

(vi) =Slides, Right and Left, and Check Lever.=

Pull out the slides. Drive out the fixing pin from the check lever collar, remove the collar and check lever.

(vii) =Recoiling Portion.=

Fold back the connecting rod on to the crank, turn the crank handle to a vertical position, and draw out to the rear the recoiling portion. Disconnect the side plates by dropping them and springing them outwards. If necessary, by taking out the fixing pin, the crank handle can be driven off with a drift and hammer, and the fusee unscrewed from the left bearing of the crank; but as a rule these parts should not be stripped.

(viii) =Foresight.=

The position of the foresight should first be carefully marked. Remove the fixing screw and foresight.

(ix) =Steam Tube and Packing Gland.=

Up-end the barrel casing so that it stands on the rear end of the breech casing. Remove the keeper screw and unscrew the steam tube. Unscrew and remove the packing gland and packing.

(x) =Breech and Barrel Casings, and Ejector Tube Spring.=

Rest the barrel casing on a table or bench, with the filling hole uppermost, and the breech casing clear of the bench; place the left hand under the breech casing and strike the top edges alternately with a mallet, when the casings will come apart. Lift the ejector tube spring with the point of the screwdriver and tap out the spring with the drift and hammer. (In converted guns remove fixing wire and unscrew fixing screws.)

NOTE.—The breech and barrel casings should only be separated when repairs are necessary. Care must be taken not to strike the barrel casing, and the blows should be struck as close to the dovetailing as possible.

(xi) =Lock.=

(_a_) Release the lock spring, lay the lock on a bench, left side uppermost. Drive out the sear, tumbler, and lock spring axis pins. (_b_) Remove the keeper bracket, extractor levers, lock spring, tumbler, firing pin, and sear. (_c_) Drive out the trigger axis pin, extractor stop keeper pin, remove the trigger, extractor stop, and slide the extractor from the face of the lock casing. (_d_) Push out the gib spring cover, take out the gib spring and gib. (_e_) Drive out the extractor spring fixing pin, and remove the extractor spring. (In converted guns the extractor spring is riveted to the extractor.)

NOTE.—(_e_) should only be done in case of breakage.

(xii) =Feed Block.=

(_a_) Drive out the spring fixing pin of the top and bottom levers, drive out the bottom lever and remove the top lever and slide. (_b_) Drive out the axis pin of the bottom pawls and remove pawls with feed block spring. (In converted guns unscrew fixing screws and remove feed block springs.) (_c_) Drive out the fixing pin of the band roller axis pin, remove the collar, axis pin, and band roller. (_d_) Remove the top pawls from the slide by pressing them outwards. The springs for the pawls, if weak or broken, are only to be removed by an armourer or qualified artificer.

(xiii) =Tangent Sight.=

(_a_) Remove the top fixing screw of the graduated plate. (_b_) Run the slide off the stem. (_c_) Remove the fixing screw of the milled head, and lift the latter off the slide. (_d_) Remove the fixing pin, pawl and pinion from the slide. (_e_) Place the milled head, face upwards, on a bench; then with a drift, applied to the rectangular nib on the spring slide, knock the latter down flush with the face, when it can be lifted out with the pliers.

(xiv) =Rear Crosspiece.=

(_a_) Drive out the axis pin of the firing lever, and remove the latter with its spiral spring. (_b_) Drive out the axis pin of the safety catch, and lift out the latter, also the piston and spring from their seating. (_c_) Remove the pivot screw and shutter. (_d_) Unscrew, from the handles, the milled heads with their leather washers and oil brushes.

EXAMINATION AND TESTING.

Before assembling the gun all parts should be tried in their places separately to see that they work freely, and test friction of recoiling portions as follows:—

Cock lock, remove fusee spring box and spring, turn crank handle upwards, hold it with right hand and fusee with left, move recoiling portion, with gun horizontal, backwards and forwards, to see that it works freely and that barrel goes home. Weight necessary to move recoiling portion should not exceed 4 lbs. (converted guns 7 lbs.) tested by placing loop of spring balance over knob of crank handle, and pulling to rear when handle is slightly above the horizontal.

ASSEMBLING THE GUN.

Reverse all the foregoing operations with the exception that the recoiling portions must be replaced before the packing and packing gland. In order to assemble the barrel and breech casings, they will have to be turned upside-down—_i.e._, the filling hole down, and the bottom plate of breech casing uppermost—they should be positioned by the crosshead joint pin. Care must be taken that the ejector tube spring is in position before joining the casings together. When assembling the feed block the longer of the two bottom pawls must always be placed at the front. When assembling the tangent sight, it will be found convenient to place the slide on the stem before attaching the milled head; in this position the pinion is prevented from turning with the pawl when engaging the arms of the slide spring outside the lugs in the pawl.

REPLACEMENT OF DEFECTIVE PARTS OF THE LOCK.

Should any of the components belonging to the lock become defective they can be replaced from the spare parts, without stripping the lock right down. Proceed as follows:—

(i) =Sear.=

Fully cock, lift the sear, and let the firing pin engage with the tumbler and trigger; with the lock on the bench, left side up, drive out the sear axis pin, and remove the sear with its spring.

(ii) =Tumbler.=

Fully cock, thus engaging the firing pin with the sear; drive out the axis pin of tumbler, pull the trigger slightly, and lift out the tumbler.

NOTE.—Care should be taken not to allow the screwed head to lift the sear when once the tumbler has been removed.

(iii) =Trigger, Lock Spring or Extractor Levers.=

Release the lock spring, drive out the lock spring axis pin, remove the keeper bracket, extractor levers and lock spring; if the trigger is defective, drive out the trigger axis pin and remove the trigger.

(iv) =Firing Pin.=

Proceed as for (iii), but do not remove the trigger. Remove the tumbler axis pin and tumbler, raise the sear, push the screwed head out of its way, and the firing pin will drop out.

(v) =Gib, Gib Spring, or Extractor Spring.=

This will necessitate the removal of the extractor from the face of the lock casing. Release the lock spring, drive out the lock spring axis pin, remove the keeper bracket and extractor levers; next drive out the keeper pin of the extractor stop, remove the latter, and slide the extractor off the lock casing: push out the gib spring cover, and remove the spring or gib as the case may be. If the extractor spring requires replacing, drive out its fixing pin and remove.

NOTE.—The serviceable components are replaced in the reverse order.

STOPPAGES.

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│Immediate action.│ Probable cause. │ Prevention of
handle and its │ │ │ recurrence.
indication. │ │ │
─────────────────┼─────────────────┼─────────────────┼─────────────────
│ │ │
=FIRST= │(i) Turn the │The extractor has│
│crank handle on │not dropped. This│
│to the buffer │may be due to:— │
│spring, pull the │ │
│belt to the left │ │
│front, and let go│ │
│the crank handle.│ │
_Indication._ │ „ │(_a_) Too heavy │
The lock is │ │fusee spring. │
unable to come │ │ │
back far enough │ │ │
to allow the │ │ │
extractor to │ │ │
drop. │ │ │
„ │(ii) If failure │(_b_) Excessive │(_b_) Clean and
│recurs, lighten │friction, due to │oil working
│fusee spring by │want of oil; grit│parts. Examine
│three “turns.” │or tight pockets │the belt, which
│ │in the belt, or │should be dried
│ │excessive packing│if damp; or if
│ │in cannelure or │the stoppage is
│ │packing gland. │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 │(_c_) (i) The
│ │ammunition. │barrel should be
│ │ │examined at the
│ │ │first
│ │ │opportunity, and
│ │ │if much worn in
│ │ │the lead should
│ │ │be changed.
─────────────────┼─────────────────┼─────────────────┼─────────────────
│ │ │
=SECOND.= │(i) Force the │(i) (_a_) Damaged│
│crank handle on │cartridge. The │
│to the buffer │cartridge is │
│spring. Open the │unable to enter │
│cover and examine│the chamber │
│the cartridge on │completely, │
│the face of the │although it has │
│extractor. If a │commenced to do │
│damaged │so. │
│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. │ │
_Indication._ │ „ │(_b_) Separated │
The lock is │ │case with front │
unable to go │ │portion adhering │
fully home after │ │to undamaged │
recoil. │ │cartridge. │
│(ii) If an │(ii) Separated │(_b_) If a
│undamaged │case. The front │succession of
│cartridge with no│portion of the │separated cases
│front portion of │case causes an │occur the
│separated case │obstruction and │connecting rod
│adhering to it is│prevents the next│must be
│found on the face│cartridge from │lengthened.
│of the extractor,│going into the │(_See_ para. 82.)
│clear the face of│chamber. │
│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. │ │
─────────────────┼─────────────────┼─────────────────┼─────────────────
│ │ │
=THIRD.= │ │ │
_Indication._ │(i) Strike the │(i) (_a_) Too │(i) (_b_) Clean
The extractor is │crank handle on │light fusee │and oil working
unable to rise to│to check lever by│spring. │parts.
its highest │a glancing blow │ │
position. │with the palm of │ │
If the feed block│the hand. If │ │
slide is jammed, │failure recurs, │ │
there is a fault │strengthen the │ │
in feed. │fusee spring by │ │
│three turns. │ │
„ │ „ │(_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) │(ii) A cartridge │(ii) Carefully
│fails, slightly │is fed up │examine the belt.
│raise the crank │slightly │
│handle, pull the │crossways, or a │
│belt to the left │long brass strip │
│front, let go the│is bent. │
│crank handle, and│ │
│then strike it │ │
│down on the check│ │
│lever. │ │
│(iii) A. If (i) │(iii) A. (1) │(iii) A. (1)
│and (ii) fail, │Badly filled │Carefully examine
│examine feed │belt, or a belt │the new belt.
│block slide. If │with worn or │
│jammed, No. 1 │loose pockets. │
│holds up the │The cartridges │
│crank handle and │projecting │
│opens the cover. │unevenly from the│
│No. 2, with the │belt prevent it │
│assistance of No.│entering or │
│1, removes the │passing freely │
│feed block, and │through the feed │
│replaces it by │block. │
│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. (2) Belt│(iii) A. (2) See
│ │box not being in │that the new belt
│ │line with the │box is in line.
│ │feed block; the │
│ │belt does not │
│ │lead up correctly│
│ │to the feed block│
│ │and becomes │
│ │jammed. │
│ „ │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,│(iii) B. (1) │
│No. 1 opens the │Damaged cartridge│
│cover. No. 2 │grooves. │
│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. │ │
│ „ │(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 │(_a_) (1) No │
│crank handle on │cartridge in the │
│to the buffer │chamber. │
│spring, pull the │ │
│belt to the left │ │
│front, and let go│ │
│the crank handle.│ │
_Indication._ │ „ │(2) Defective │
That there has │ │ammunition. │
been no │ │ │
explosion, or, if│ │ │
any, that there │ │ │
has been little │ │ │
or no recoil, the│ │ │
lock remaining in│ │ │
its forward │ │ │
position. │ │ │
„ │(_b_) If (_a_) │(_b_) (1) Broken │
│fails, place the │or damaged firing│
│crank handle on │pin. │
│to the buffer │ │
│spring twice, │ │
│change the lock, │ │
│and re-load. │ │
„ │ „ │(2) Broken lock │
│ │spring. │
│ │ │
─────────────────┴─────────────────┴─────────────────┴─────────────────

NOTE.—If the continued lightening of the fusee spring results in the crank handle stopping in the third position, take muzzle attachment into use, and put fusee spring back to normal weight (see para. 44).

NOTE.—Worn or damaged side or extractor levers may result in the
extractor being unable to rise, or if the side levers are bent, there
may either be a succession of separated cases, or the lock may become
jammed.

The causes of prolonged stoppages are so varied that they cannot be set out in detail. The following are amongst the most probable, and the detachment should be thoroughly trained to recognize them and to apply such remedy as lies in their power pending a permanent repair:—

(i) =Broken Cover Springs.=

The extractor may not drop when the lock is drawn back, and the gun will stop with the crank handle in the first position. This may possibly be overcome by liberal oiling of the lock, but in any case single shots can be fired by holding the crank handle forward until the extractor drops by its own weight.

(ii) =Broken Ejector Tube Spring=,

Causing either a block in the ejector tube or an accumulation of empty cases in the breech casing. It may be found possible to keep the gun in action if care is taken to prevent the latter.

(iii) =Cotter working out=,

Thus causing the screwed head and connecting rod to become separated. To remedy proceed as follows:—

(_a_) Take out the cotter. (This will be found either on the crank or
at the bottom of the breech casing.)

(_b_) Press down the screwed head with a large screwdriver to lock
the cock.

(_c_) Turn the screwdriver edgeways and insert it behind the horns of
the extractor and between the face of the barrel and front of
the lock flange, and force the lock to the rear.

(_d_) Turn crank handle on to the buffer spring, press down the
extractor, raise the lock and remove the live cartridge, then
lift out the lock.

(iv) =Damaged Parts of the Lock, no Spare Part being available.=

The gun will fire without the sear, or if the bents of the sear or firing pin are badly worn or broken off, but only single shots, and only by pressing and releasing the double button quickly.

The gun will also fire if the nose of the trigger or bent of the tumbler is badly worn or broken off, but only rapid firing. In this case the gun will fire the instant the crank handle reaches the check level, although the double button has not been pressed.

The gun can be worked as follows:—

(_a_) Group the cartridges in the belt, say 20 or 30 rounds each
group.

(_b_) Lay the gun before commencing to load, place crank handle on
buffer spring, pull belt to left and let handle go; repeat,
but before allowing the handle to reach check lever and the
gun to fire, grip the rear crosspiece with left hand to
control gun in the ordinary way.

If necessary firing can be stopped by throwing the filled end of the belt over the breech casing to the left.

When the firing has been stopped as described above, hold the crank handle with the right hand, open the cover, press down the horns of the extractor, draw the lock back, and, if there is a live cartridge on the face of the extractor, remove the feed block and belt, close the cover, and allow the lock to fly forward, when the live cartridge, which is on the face of the extractor, will be fired automatically. The lock can then be changed with safety. On no account should the lock be allowed to fly forward until the feed block has been removed and the cover shut.

If, on drawing the lock back, it is found that there is no live cartridge on its face, the lock may be changed at once, and the necessity for removing the feed block and the subsequent precautions will not arise.

(v) =Gunmetal Valve Working Loose.=

This will prevent the barrel from going home. It may be temporarily remedied by tapping it round with a hammer and punch, but it should be tightened at the earliest opportunity with the gib key, the barrel being removed from the gun.

·303–inch Vickers Gun.

Explanation of Plates IV and V.

Similar numbers indicate corresponding parts in all the plates.

1. Casing, barrel.

2. Tube, steam.

3. Bracket, foresight.

4. Gland.

5. Casing, breech.

6. Cover, front.

7. Cover, rear.

8. Sight, tangent.

9. Bar, trigger.

10. Lock, rear cover.

11. Rear-crosspiece.

12. Lever, firing.

13. Lever, trigger bar.

14. Catch, safety.

15. }
} Plugs, screwed.
16. }

17. Protector, screwed, condenser boss.

18. Plug, cork.

19. Guide, front barrel bearing.

20. Crosshead.

21. Cams, right and left.

22. Steps of cams, right and left.

23. Catch, front cover.

24. Pin, screwed, joint cover.

25. Pin-T, fixing, rear-crosspiece.

26. Pin, screwed, fixing, crank handle.

27. Slides, right and left.

28. Roller.

29. Pin, screwed, joint, rear-crosspiece.

30. Bracket, check lever.

31. Lever, check.

32. Bracket, elevating joint.

33. Stop, mounting.

34. Plate, bottom, breech casing.

35. Shutter, sliding.

36. Hooks of front cover catch.

37. Hole for keeper pin, front cover catch.

38. Lever of catch, front cover.

39. Grooves in front cover catch to clear “36.”

40. Plunger, front cover catch.

41. Bridge, rear cover.

42. { Spring tangent sight.
{
{ Piston „ „

43. Grooves in rear cover for ribs on “5.”

44. Ramps, rear cover.

45. Spring, rear cover lock.

46. Spring, trigger bar.

47. Lug on trigger bar for “46.”

48. Base of tangent sight stem.

49. Hooks of rear cover lock.

50. Lug on rear cover lock for “45.”

51. Slot in trigger bar for “86.”

52. Lug on trigger bar for “13.”

53. }
} Thumbpiece, sliding shutter catch.
54. }

55. Plunger, sliding shutter catch.

56. Arms of rear-crosspiece.

57. Grips, rear-crosspiece.

58. Pawl, firing lever.

59. Spring, safety catch, with piston.

60. Pin, screwed axis, safety catch.

60A. Finger grips, safety catch.

61. Pin, screwed, axis, firing lever.