Manual / Guide · 1918
The Royal Air Force's April 1918 instructional notes on the Lewis gun as an aircraft weapon. The Lewis Gun dive cites it for the air-service guns and their handling.
This is a reproduction of a library book that was digitized by Google as part of an ongoing effort to preserve the information in books and make it universally accessible. https://books.google.com F.S. Publication No. 37. 5 340 FOR OFFICIAL USE ONLY. 425 gt. But 000079674 SOUTHERN UC REGIONAL LIBRARY FACILITY A Royal Air Force. C [MIS . PUBS. I INSTRUCTIONAL NOTES ON THE 8 LEWIS GUN. of Califor R n egional F ✓ acility nia JED BY THE GENERAL STAFF. APRIL, 1918. N.B.-Heavy Type applies to GROUND GUN only. ROYAL AIR FORCE . INSTRUCTIONAL LEWIS NOTES ON THE GUN . SUB - HEADS OF TRAINING . 1. Hints for Squad Instructors. 2. General Description. 3. Drill . 4. Stripping . 5. Mechanism . 6. Care and Cleaning. 7. Immediate Action . 8. Secondary Action. 9. Causes of Stoppages and Setting up Gun. 10. Points Before, During, and After Flight ; or Range Practices. 11. Examination of Gun. 12. Minor Repairs and Adjustments. 13. Spare Parts. 14. Testing of Ammunition. 15. Aiming Instruction (Deflection Practice). I.-HINTS FOR SQUAD INSTRUCTORS . (1) Always inform squad what is the subject of instruction, and the object of the lesson. (2) Make sure that every member of the squad fully understands each item or part of the subject, before proceeding to the next. (3) Talk to the squad, not to the gun. (4) Do not shout ; talk just loud enough for ail the squad to hear. (5) Illustrate each point as you explain it ; do not try to explain without the use of a diagram anything that cannot be seen. (6) Be brief ; do not dwell on non-essentials. (7) Always have kit ready to commence each lesson at the hour appointed. (8) Keep a record of the progress made by every member of the squad. (9 ) Make yourself acquainted each evening with the next day's work, and prepare your instruction carefully. (10) The success of a squad depends largely on the zeal and ability of the instructor. (35502)-Wt. W5951/PP1419. 6,000. 3/18. L. & S. Ltd. 1016 GH . 1 . (16008)-Wt. 8667/804. 4,000. L. & S. Ltd. 1056 . 2 (11) The method of instruction should, wherever possible, be based on the following sequence :(a) Demonstration. (6) Explanation. (c) Imitation. (d) Interrogation. NOTE.- (a) During the hours of instruction, except at the actual firing-point on the range, live ammunition must never be brought near the Lewis Gun. It follows, therefore, that when magazines are being filled with live rounds, the work should be done at some distance from the gun. (b) Two kinds of dummy cartridges are issued by Ordnance for instruc tional purposes : i. Wooden dummies to shew the movement of the ammunition inside the gun, action of the feed, mechanism, stoppages, etc. ii. Metal dummies which should only be used as tools for stripping. (c) Neither instructors nor pupils should ever stand opposite to the muzzle of the gun, nor should they pass in front of it. II -GENERAL DESCRIPTION. The teaching of this branch of the work calls for a considerable effort of memory. It should, therefore, be taken in short sections, each of which should be thoroughly understood before passing on. The general description should be brief, the main idea being to call the attention of the pupils to the peculiarities of the various parts, with a view to their subsequent understanding of the mechanism of the gun. It has been necessary to introduce in a few places parts not yet taught, for the clearer explanation of the particular portion under consideration. On the rare occasions when this is necessary, the instructor should refer to the unknown part without giving its name. The stage at which each new name should be introduced is indicated by italics. The instruction in general description should proceed as follows : (a) Demonstration. The instructor strips the gun as far as necessary and shews in turn the parts under consideration. (b) Explanation. The instructor (i) Gives the official name in each case (taking care that the pupils acquire it correctly). (ii) Explains the purpose of this part (without encroaching upon the teaching of mechanism). (iii) Shews its relation to the rest of the gun. (c) Squad Practice. The pupils give short description of the parts, using correct names. (d) Interrogation. By a few rapid questions covering the whole of the section that is being dealt with, the instructor tests the pupils' knowledge of the names and parts. A.-GENERAL DESCRIPTION OF GUN . A short general account of the gun should first be given, so that the pupils may get an elementary idea of what the gun is and what it can do, and that their interest may be aroused. This description should not take more than a few minutes, and should touch on the following points :Name : 303 in. Lewis Machine Gun, and why so called. Weight : Ground Gun (Mark I) 26 lbs. Aerial Gun (Mark II) 17 lbs. 3 How operated : The force of the gas. The return spring. Explain briefly : (a) How the gun is loaded and fed. (b) How gun is fired. (c) How gas operates piston and other moving portions. (d) How return spring operates piston and bolt . (e) How gun is cooled. NOTE. This should be general, without the mention of names. Avoid talking of things that cannot be seen. Detailed explanations will come later when the gun is stripped. Advantages : (a) Lightness. (b) Compactness. (c) Reliability. (d) Rapid rate of fire. Disadvantages : (a) Smallness of magazine supply. Suitability for Aerial Work : (a) Well adapted for use as a mobile gun in an aeroplane. (b) Allows large field of fire. (c) Can be mounted on the top planes as well as in the fuselage. B.-GENERAL DESCRIPTION OF PARTS . The gun is divided into two portions : - (1) Stationary portions. (2) Moving portions. STATIONARY PORTIONS . These consist of :- (a) The Barrel Group. (1) The Body Group. ( a) Barrel Group : 1. Barrel. Calibre 303 in., number of grooves, 4 ; twist of rifling, right-handed. NOTE. For the purpose of demonstration, the spare barrel should be shewn. It is threaded at the muzzle to take the Barrel Mouthpiece, which has a left-handed thread to prevent it from working loose, or becoming detached from the barrel during firing. In the Mark II gun this thread is utilized. to take the nut which secures the Norman Vane Foresight. A Gas Vent is bored in the barrel 4" from the muzzle to allow the gas to pass into the gas chamber. Around this vent, in the thickness of the barrel, is a conical recess with a flat base. On the top of the barrel , near the rear end, is a Stud which fits in a slot in the radiator , ensuring that the gas vent is in position to receive the gas chamber. In the Mark II gun, this stud lies between. two positioning studs on the under side of the flat surface at the rear end of the barrel casing. Behind this stud is a Collar which determines the position of the barrel in the casing. Behind the collar a Square Thread is cut for attachment to the body. On the rear face of the barrel is a projection which coincides with the cut- away portion of the bolt face when the breech is closed. By this means the rim of the cartridge is held away from the barrel, so that the extractors are able to grip it, while at the same time the base of the cartridge is efficiently supported. The upper part of the entrance to the chamber is slightly sloped, to direct the nose of the bullet downwards. 4 Surrounding the barrel is the Radiator , which is of aluminium , has projecting flanges , and is split longitudinally. It assists in dissipating the heat of the barrel . At the forward end, on the under side , is a recess for the gas chamber . At the rear end , on the upper side , is a flat which corresponds with another flat on the radiator casing to ensure an alignment . 2. Radiator Casing. Around the barrel and radiator is the Radiator Casing, which consists of front and rear portions , connected by a Clamp Ring. The rear portion has a hole cut in it to allow for the entrance of the gas regulator , and a small hole to take the stud of the gas regulator key . The rear face is drilled to admit and hold in position the barrel and gas cylinder . There is also a small hole drilled for the body locking pin . The front portion is tapered , and extends beyond the barrel mouthpiece. On both portions are collars which take the clamp ring , slots being cut to accommodate the stud on it . The clamp ring is turned up at both ends to form a foresight protector , and the inner portion on the right side forms the foresight block, and is dovetailed to receive the foresight. The clamp ring is held in position by the Clamp Ring Screw. On the upper side of the radiator casing and at the rear, is a flat surface, the casing being cut away immediately in front for cooling purposes . In the aerial gun the casing is in one piece, known as the Barrel Casing. There is no radiator, and the casing is of smaller diameter, except at the rear end, where it is of the same size as the ground gun. At the front end are two holes, one to take the gas regulator and one to take the stud on the gas regulator key. A small hole is drilled in the rear face to take the body locking pin. At the rear end are two bands, one of which takes the Mounting Yoke, and the other the Ring Sight. 3. Barrel Sleeve. In the aerial gun the barrel is supported at the front end by a Barrel Sleevc. This fits the casing exactly, but is fretted for cooling purposes. Its body is cut away to allow the barrel band to be inserted . 4. Barrel Band. Fitting closely round the barrel, and over the gas vent, is the Barrel Band . Being tapered, its correct placing is ensured by keeping to the front the small letter " F " stamped upon it. The band is bored and threaded to receive the gas chamber. 5. Gas Chamber. This may be one of two patterns : (a) Mark I type screws into the barrel band by means of a Nipple chamfered away at the end to fit tightly into the conical recess in the barrel. Its rear face is threaded to receive the gas cylinder. The chamber is hollowed out to take the gas regulator. On its circumference there are two wings which provide a grip for the spanner. (b) Mark II type embodies :-- (i) A ring which fits round the barrel and takes the place of the barrel band in the Mark I pattern. ( ii) A vertical seating threaded internally to take a screwed plug. ( iii) A horizontal seating into which the gas cylinder screws. The Screwed Plug has a left-handed thread, and is recessed at the top to take the barrel mouthpiece spanner. It has eight holes drilled through the cylindrical portion, and is threaded internally to take the gas regulator. The plug plug is kept in position by a Keeper Screw. The holes and recesses are so arranged that when the keeper screw is in one of the recesses, one of the holes is opposite to the gas cylinder. 6. Gas Regulator. Screwed into the gas chamber is the Gas Regulator, the object of which is to regulate the amount of gas admitted to the gas cylinder. For this purpose it has two holes of different size, either of which can be placed opposite the hole in the rear face of the gas chamber. 5 The position of these holes is indicated by the letters Land S (meaning large or small) stamped on the exposed end of the regulator. 7. It is held in position by means of the Gas Regulator Key, for which a square hole is cut through it. The key is held in place by a stud at its rear end, which enters a hole in the casing, a loop being provided immediately above to enable the point of a bullet to be used for springing the key out of the hole. S. Gas Cylinder. This is a tube shaped at the rear end to admit the rack on the piston rod. Its forward end screws on to the gas chamber. Mark I and Mark II cylinders differ in their manner of attachment to the gas chamber, and can only be used with Mark I and Mark II gas chambers respectively. NOTE.--Great care should be taken to preserve the threads and to prevent the flattened portion from being damaged by the rack in stripping. (b) Body Group : 1. Body. This has a square thread for attachment to the barrel. Bottom. Underneath the body is the Housing for the Body Locking Pin, in which lies the dumb-bell shaped Body Locking Pin that ensures and maintains the correct relative placing of body and barrel. At the side is a groove for the insertion of the nose of a bullet to withdraw the pin when stripping. Immediately to the rear is the Pinion Hinge Pin, on which the pinion casing is hooked. Openings are cut to allow the pinion, plunger and sear to enter the interior of the body. There are also grooves in which the trigger group slides. Behind the grooves is a slot into which fit the lower projections of the butt cap. Sides . On either side of the body is a slot in which the shank of the cocking-handle can travel. Each slot can be covered by a plate sprung into position and moved vertically by a thumb-piece. This plate serves as a Safety Catch or Dust Protector, the recesses in it holding the cockinghandle, whether in the forward or backward position. On the right hand side of the body is the Ejection Opening. Top. Near to the front endis the Magazine Post, which is hollowed and countersunk to take the magazine catch. On the exterior of the post is a key which fits into a groove in the centre block of the magazine, and near the base at the front is a saw-cut. The magazine post can be lengthened to take Mark II magazines by the addition of an auxiliary Magazine Post. The top of the body is slotted throughout the greater part of its length, the front of the slot taking the shape of a cartridge, while the rear portion acts as a guide to the boss on the feed arm actuating stud. Near the front end of the cartridge-shaped slot, on the left, is a small groove, which coincides with a depression in the front portion of the feed arm. Near the rear end of the cartridge-shaped slot are two projections which keep the cartridge in position until the bullet enters the chamber. At the rear end, on the right side, is a groove which guides the rim of the cartridge. On the left side of the slot lies the Ejector Seating, which is closed by an Ejector Spring Cover sprung into position, and held at its forward end by grooves cut in the body. At the bottom of the seating is a hole into which fits the stud on the under side of the ejector. The Ejector is hook-shaped and is pivoted on a stud on its under side. It is slightly cranked, in order that, while keeping its head in line with the slot in the face of the bolt, its tail may be in position to be actuated by the lug on the bolt. At the rear of the body is a shallow channel in which moves the stud on the tail of the feed arm. 6 The rear part of the top of the body has running round it a raised portion which is flanged and under cut in places, to retain the body cover in position. The curved portion of this, at the front on its left side, acts as a stop to the forward movement of the body cover. At the front end, on its right side, is a small flat portion, which acts as a guide for the cartridges. The extreme rear part of the top of the body forms a bridge, above which is a raised platform, which gives strength and helps to position the body cover. Interior. Inside the body are drilled the Bolt-way and the Piston-way. The bolt way has four Cruciform Guide-ways, or grooves in the form of a cross, which admit the lugs on the bolt and on the feed arm actuating stud. At the forward end of the bolt-way are the Locking Recesses , in which the resistance lugs on the bolt lie when the breech is closed. Near the rear end of the bolt-way are recesses in which the interrupted flanges of the butt cap engage. On the left of the bolt-way, slots are cut to allow the head and tail of the ejector to project alternately into it. The piston way is flat-bottomed to take the rack. 2. Body Cover. This is shaped to fit on the top of the rear portion of the body. At its front end is a projecting Tongue, on the under side of which is the seating for the cartridge guide spring. The Cartridge Guide Spring is held in position by an under-cut recess, andhas a stud which fits in a hole in the tongue. The left leaf is turned over ; the right leaf is in the form of a flat spring turned in and positioned at its free end by the left leaf. The Cartridge Guide, which is superseding the cartridge guide spring, fits in exactly the same way. Its right leaf is similar in shape, but it is hinged and operated by a flat spring. Behind the tongue is the Housing for the Stop Pawls, of which there are two, pivoted on studs. The Left Stop Pawl (marked 1) is the nearer to the top of the housing. The Right Stop Pawl (marked 2) has an enlarged head which brings it on a level with the under side of the body cover, and also prevents undue friction between the pawls themselves. Each stop pawl has a short tail which bears against the sides of the body cover and limits its movement. When Double magazines are used, the pawls need to be bevelled to avoid the lowest rivets on the magazine. Behind the pawls is the Stop Pawls Spring, a flat spring which tends to push their free ends forward. On its rear face is a stud by which it is positioned . At its left end a small portion is turned over to grip the right stop pawl, so holding both stop pawļs down on their studs. At the back of the housing is a hole which accommodates the stud on the stop pawls spring. Behind this hole is a groove for the insertion of the nose of a cartridge. For lightness and the reduction of friction, the body cover is milled out, with the exception of two Ribs, which strengthen the cover and also act as a bearing surface for the feed arm. The body cover has round it a raised portion which corresponds with that on the body. At the rear end this raised portion fits over the raised platform on the body. 3. Pinion Casing. This is hollowed out to contain the pinion and return spring. At the front end is a hook which connects it to the body ; this is cut away to accommodate the body locking pin, and slotted to allow the casing to be removed when the pistol grip is drawn back. At the rear end is the Pinion Paul, which has two arms set at right angles, and is pivoted, One arm is actuated by a U spring bearing against it from behind ; the other arm projects from the casing. When the trigger group is not in position, the former engages in the pinion to prevent the spring from unwinding. When the trigger group is in place, the projecting arm of the pawl is lifted so that the other arm is withdrawn from the pinion, leaving the pinion free to revolve. The casing is drilled to take the Tension Screw, and has shoulders which prevent that screw and the hub 7 from turning when the pinion and return spring revolve. Internally it has on one side a shallow recess which accommodates a circular projection on the pinion. The Pinion is a hollow casing which forms one half of a drum, and is bored centrally to take the tension screw. On its outer circumference are 52 teeth, while its inner circumference has a recess into which a correspond . ing projection on the spring casing enters, causing the two parts to move as one . The Spring Casing contains the Return Spring, which is flat and coiled and has its outer end anchored by two studs which fit into two slots in the rim of the casing. The inner end of the spring is turned over to fit into a slot in the Hub. The latter is bored and threaded to take the tension screw . 4. Trigger Group. This is held in the grooves on the under side of the body. It is a frame which is channelled at the top to contain the plunger, the trigger, the sear, and the butt catch. The lower part of the frame forms the Trigger- Guard and Pistol Grip. Externally it has grooves cut along the top edge, while at its front end is a recess for the projecting arm of the pinion pawl. The Plunger is a hollow cylinder with a slot to take the front end of the trigger. It contains the spring by which the trigger is actuated, and serves to position the pistol grip frame when the spade grip is removed. The Trigger, which is pivoted on an axis pin, has two arms, the forward one of which engages with the plunger, while the other has at its rear end a claw. The Sear is also pivoted on an axis pin and has two arms, the front one engaging with the claw on the trigger, while the rear end of the other forms the sear Nose. At the rear end of the pistol grip frame is the Butt Catch, which is operated by a spiral spring and is secured by a fixing-pin. 5. Spade Grip. This is fitted to the rear end of the body and comprises the Butt Cap and a Handle. On the cap is a stud with four cruciform lugs by which the spade grip is attached to the body. Below this stud is a projection with a recess into which the butt catch fits. The handle is covered with leather and hollowed out to form a reservoir for oil, this reservoir being closed by a milled-head screw to which is attached a camel hair brush . MOVING PORTIONS . 1. Piston Rod. This is in two parts, joined by a loosely fitting thread secured by a pin, an arrangement designed to compensate for any want of alignment between the cylinder and the body. The piston Headis cupped, and has four Rings with the same number of Grooves : these tend to hinder the escape of gas, to clear away fouling, and to reduce friction. Under the rear portion of the piston rod is a Rack having 60 teeth. Behind the rack is a Bent which engages with the nose of the sear. On the top of the piston rod is the Striker Post, which is drilled for the Striker, the latter being secured by a fixing pin ; the striker post is cammed at the front left and right rear side, so as to work in conjunction with similar cam surfaces on the siot in the bolt. The rear end of the piston rod is cut away at the sides for lightness and the reduction of friction. Behind this cut-away portion is a slot which takes the shank of the cocking-handle. The Cocking -handle has a flat Shank which fits into the slot in the piston rod. On this shank are two shoulders which secure the cocking-handle in the slots in the side of the body. cupped for the sake of lightness. The Head of the cocking-handle is 8 2. Bolt. This is a hollow_cylinder. Its face is pierced by the Striker Hole, and has a rim which supports the base of the cartridge, gaps being cut to accommodate the extractors, the cartridge rim stop, and the head of the ejector. The two Extractors are flat springs, each of which fits into a recess or Extractor Seating cut in the outer surface of the bolt. At the front there is a claw which grips the rim of the cartridge, and a stud which sinks into a hole in the seating. The rear end is shaped to fit into a groove which positions it securely. Lengthwise in the bolt is cut a Cam Slot in which the striker post travels. At the rear end of the bolt are four Cruciform Resistance Lugs which fit the Cruciform Guide-ways in the body. These are all rounded off at the right rear corner to facilitate their rotation into the locking- recesses. The top lug is flattened to allow free movement of the feed arm , while the left one is slightly cut away to admit of free movement of the tail of the ejector The bolt is threaded internally at the rear end, and its rear face has two shoulders which act as stops for the feed arm actuating stud. 3. Feed Arm Actuating Stud. This is threaded externally to screw into the rear of the bolt , and has two square stops to correspond with the two on the bolt. It has four Cruciform Guide Lugs which also fit the cruciform guide-ways. On the topmost lug is the Boss of the Feed Arm Actuating Stud, a heart -shaped stud which works in the rear part of the slot in the top of the body and operates the feed arm. 4. Feed Arm: This has at its front end a hole which passes over the magazine post on which it pivots. A hinged Latch secures the feed arm to the magazine post by engaging in the saw- cut on its base. A slot called the Feedway is cut in the feed arm to allow the cartridges to pass from the magazine to the body. A small depression and turned-up portion on the left acts as a Bullet Stop ; this keeps the cartridge in position during the movement of the feed arm to the left. Slightly further back is the Cartridge Stop, which prevents the cartridge from jumping up after leaving the cartridge guide spring. The raised portion forming the cartridge and builet stops is interrupted by a small cut- away part which allows clearance for the separating pegs of the magazine. Further to the rear are three studs. The largest is the Feed Pawl Spring Stud, which positions one end of the Feed Pawl Spring. The next in size is the Feed Pawl Stud, which serves as a pivot for the Feed Pawl. The smallest is the Feed Pawl Stop Stud, the function of which is to stop the forward movement of the feed pawl. The Feed Pawl has a slot in which its spring lies, and its under side is recessed to accommodate the other end of the spring, which is positioned by the Feed Pawl Spring Retaining Stud. The Tail of the feed arm is curved and grooved on its under side to receive the boss on the actuating stud. At the end of the tail is a positioning stud which engages with the top lug of the bolt when the latter reaches its limit of movement to the rear, thus holding the feed arm in position until the boss on the actuating stud again enters the groove in the tail of the feed arm. THE MAGAZINE, This is a circular pan with 25 rectangular Indentations or Corrugations on the rim. Inside these, plates are riveted to hold the bases of the cartridges. A circular hole is cut in the centre of the pan, 25 Recesses being cut round the edge of this hole. The hole is covered by a Disc which has a circular channel on its under side for the Magazine Catch . The catch is shaped to fit this channel, and has a projecting Tongue with a Nib at the end, the nib being intended for engagement with the recesses mentioned above. Opposite to this tongue is placed the Magazine Catch Spring, which tends to keep the nib pressed into one of the recesses. A ring carrying 25 Separating Pegs is riveted round the central hole. These 9 pegs and the indentations on the rim hold the cartridges in position, and carry them round when the magazine is rotated. Projecting from the magazine catch into the hollow magazine post is a sloping thumb -piece terminating in a hooked portion which engages in a recess below the counter-sunk portion of the post and so holds the magazine on to the gun. To the under side of the centre disc is riveted an aluminium Centre Block which has a spiral channel connected by a ramp to accommodate the noses of the bullets. In the centre is the hole for the magazine post, and a Key-way is cut to fit the key on the magazine post. The magazine catch locks the centre block to the pan and prevents the latter from rotating when the magazine is not in position on the gun. Magazines are of two types : (a) Single Magazines. These hold 47 cartridges and weigh when empty 1 lbs.; when full 41 lbs. (b) Double Magazines. These hold 97 cartridges and weigh when empty 3 lbs.; when full 8 lbs. , 14 ozs. " SPEEDED - UP LEWIS GUNS." In order to make Lewis Guns more certain of functioning at high altitudes with the double magazine, and also to increase the rate of fire, Conversion Sets are being fitted, consisting of the following components : ( 1) Mark 1 * Barrel. (2) Mark 1 * Gas Regulator. (3) Plug and Volute Spring. Mark 1 * Barrels are special to the speeded-up Guns and have a flat near the muzzle on which they are marked 1 * A.S. They have a larger gas hole but are otherwise the same as a Mark 1 Barrel. Mark 1 * Gas Regulators are also special to the Speeded-up Gun and are reduced in internal capacity by the insertion of a plug, shaped to guide the gases straight into the gas cylinder. A slot is cut in the underneath surface for easy identification, and the Regulator is marked 1 * A.S. The Mark 1* Barrel and the Mark 1* Gas Regulator, when fitted to the gun in place of the standard barrel and gas regulator, increase the blow of the gases on the piston rod, thereby increasing the velocity of the backward movement of the recoiling parts. The Plug isfitted into the rear end of the piston rod, with its flat end to the rear. The Volute Spring is then inserted so that its smaller end protrudes to the rear and provides a buffer between the piston rod and the spade grip. This spring serves to absorb some of the extra energy, due to the greater velocity of the backward movement of the recoiling parts and gives some of this energy back for the purpose of increasing the velocity of their forward movement. The velocity of the backward movement is therefore increased by the larger gas hole and special gas regulator, and the velocity of the forward movement is increased by the Volute Spring which, in addition, serves to minimise the blow on the spade grip and to prevent fractures . HAZLETON MUZZLE ATTACHMENT. This is still being used as a temporary means of speeding up the gun until the adequate supplies of the Conversion Sets mentioned above are available. It is screwed on to the muzzle and speeds up the gun by allowing more of the gases to be trapped. IMPORTANT.-H.M.A's and the Conversion Sets must never be used together, as otherwise excessive breakages would result. 10 III .-DRILL. 1.-GENERAL REMARKS . ( 1) The objects of the drill are :(a) To accustom the gunner to handle the gun and to change magazines cleanly and correctly. (6) To train the gunner in certain movements till they become automatic, so that no time may be lost in opening and maintaining the fire of the gun during action. (2) Double magazines should always be used. (3) The gunner will repeat all orders. (4) In the early stages no time limit should be set. This may be introduced later and gradually reduced as proficiency is attained. (5) Streamlining to meet various directions of slipstream should be practised. (6) When the pupils are proficient, drill should be carried out with the gun in various positions, e.g., the gunner may sit with his legs between the short legs of the tripod, the long leg of which then points towards the target. (7) Further practice should be given in a fuselage, or with a Scarffor other mounting fixed on a stand 2.-KIT REQUIRED . (1) Gun with ring sight and mounting. (2) Six magazines, with one dummy in each. (3) Model aeroplane, for use as a target. (4) Tripod. (5) Ground sheet, when working in the open. POSITION OF GUN. (1) Mounted on the tripod. (2) Muzzle pointed to the ground. (3) Target at 10 yards distance. (4) Six magazines, placed on the right of the tripod. 3.-PRELIMINARY . On the command " Fall in ! " the squad takes up position in line, 5 yards in rear of the tripod. The squad then numbers. Each detail should see that the magazines are placed on his right, with the luminous paint to the rear and the lip of the centre-block in the correct position. 4.-METHOD OF TEACHING . (a) Demonstration : Instructor demonstrates :- (i) Complete drill, taking care to set an example of clean and correct action . (ii) The section about to be taught. (b) Explanation : Instructor explains in detail the section to be practised, shewing clearly the various points to be observed. (c) Squad Practice : Each member of the squad carries out the section just demonstrated and explained. The Instructor criticises after each attempt. (d) Interrogation : Instructor tests Pupils' knowledge of the sequence of the actions and of the points to be observed, 11 Command. I. Detail of Gunner's Action. " No .... Detail, ( 1) Double to tripod. take post ! " (2) Take up position on seat. (3) Place gun in position for loading :(a) Place right hand on spade grip. (b) Lower gun. II. " Load ! " ( 1) Place magazine on post :- (a) Grip magazine firmly with both hands, putting thumbs across the upper surface and fingers under the centre -block. (b) Streamline magazine on to post. (c) Test magazine catch by a sharp upward pull on magazine before releasing grip. (2) Put gun in firing-position : - (a) Grasp spade grip firmly with right hand. (b) Raise gun to horizontal position, at the same time pulling back cocking-handle smartly with left hand. (c) Grasp pistol grip with left hand. III.- " At aeroplane ! " ( 1 ) Take aim :(a) Plant feet firmly on ground. (b) Place elbows firmly on the inside of the thighs, keeping the knees apart. (c) Grip gun firmly, pressing inwards with both hands, and placing thumb on the top of the spade grip. (d) Rest chin on thumb. (e) Align sights on mark. IV. " Fire ! " (1) Press trigger. (2) Release trigger. (3) Keeping the eye on the mark, strike magazine a glancing blow towards left front, using palm of left hand. NOTE. This movement should be made from the elbow, and the hand at the moment of striking the magazine as near vertical as possible. (4) Lower gun till pistol grip rests on tripod. (5) Change magazine :(a) Grip magazine as before. (b) Release catch with left thumb. (c) Stream -line magazine to left side of tripod. (d) Place on next magazine in same manner as before. NOTE. Repeat II, III and IV until all magazines have been used. 12 Command. Detail of Gunner's Action. V.- " Unload ! " and ( 1) Remove magazine. (2) Raise gun to firing-position, and keeping " Clear gun ! " the eye on mark, pull back cockingcocking- handle 3 times, keeping trigger pressed (3) Raise gun and place it so that the muzzle points to the ground, taking care that the gun does not strike the tripod with any force. (4) Report " Gun clear ! " VI. " Stand Clear ! " Rise from seat and retire to position in squad. NOTE 1.—In actual practice on the range, there may be a round in the feed arm . NOTE 2. This round is thus fired. To remove round from the feed arm when it is not safe to fire : - Hold back the cocking-handle with the left hand and press the trigger with the right hand. Allow the cocking-handle to go slightly forward. Insert screwdriver through the ejection opening (after opening deflector bag) and press on the under side of the shoulder of the cartridge. Allow the cocking-handle to go forward slowly ; the cartridge will roll out to the right on the top of the feed arm. TEST : - (1) 6 Magazines to be used with a dummy cartridge in each. (2) Gun to be loaded, aimed and fired ; magazine to be rotated and changed. ( 3) Repeat until the 6 magazines have been used. (4) Gun to be un-loaded and cleared. Time allowed--1 minute. IV .-- STRIPPING. 1.- GENERAL REMARKS . ( 1 ) Stripping guns should be used for instructional purposes. (2) No time limit will be imposed ; ability to strip a part correctly, (or in the case of instructors to teach how it should be stripped correctly) will form the basis of all stripping examinations. ( When pupils are proficient, time tests are permissible). (3) For stripping the Mark II gun, the only tools necessary are : -a dummy cartridge with a metal-pointed bullet and a barrel mouth -piece spanner . (4) When stripping, all parts are to be laid out in order and so placed that they will be kept clean and undamaged. (5) With reasonable care, defects and breakages should be of extremely rare occurrence. They are simply due to the neglect of ordinary precautions. 13 2. SEQUENCE OF STRIPPING MARK II GUN. ( 1 ) Spade Grip. (2) Trigger Group. (3) Pinion Casing. (4) Body Cover. (5) Feed Arm. (6) Cocking-handle. (7) Piston Rod and Bolt. (8) Body Locking Pin. (9) Body. (10) Gas Regulator Key. (11 ) Gas Regulator. (12) Barrel and Attachments from Casing. (13) Gas Cylinder. (14) Gas Chamber. (15) Barrel Sleeve and Band. Pinion Casings should have a small recess cut in the front part of the hook which attaches them to the pinion hinge pin. This recess , as it clears the body locking pin, enables the pinion casing to be removed without any further steps than the release of the projecting end of the pinion pawl. 3.-DETAILS OF STRIPPING GUNS. NOTE. Before commencing to strip see that the cocking-handle is in the forward position. (1) Insert bullet in the recess behind the butt catch and force it forward. Turn spade grip of a turn to the left and draw out. (2) Keeping the trigger pressed, slide off the pistol grip. (3) Unhook the pinion casing. (4) Pull back body cover to fullest extent and lift it off. (5) Open feed arm latch, turn the feed arm till the key-way coincides with the key on the magazine post and lift it off. NOTE.-As the feed arm is easily damaged, care must be taken to keep bullet vertical when opening feed arm latch, and to avoid strain on the feed arm when handling it. ( 6) Draw the cocking-handle to the rear and pull it out. (7) Slide out piston rod and bolt, separating the two after removal. (8) Turn the gun over to the left ; push back the body locking pin with the nose of a bullet and take it out. (9) Unscrew the body from the barrel (giving 24 turns). (10) Remove the gas regulator key, placing nose of bullet in loop provided. (11) Unscrew the gas regulator. (12) Draw out the barrel and attachments from the front end of the barrel casing. NOTE. In the case of the Mark I gun , unscrew the clamp ring screw, remove the clamp ring and front radiator casing : slide the rear part of the casing off to the rear . (13) Unscrew the gas cylinder. (14) Unscrew the gas chamber. ( 15) Tap off the barrel sleeve and barrel band and separate them when removed. 14 4. -RE-ASSEMBLING . To re- assemble the gun, reverse the order and processes given above. The following points are important : ---- (1 ) See that the barrel band is placed correctly on the barrel. (The letter " F " indicates the front). (2) When screwing on the gas cylinder, see that it is quite square with the gas chamber ; otherwise the fine threads of the screw may be injured. If the piston rod is used for this purpose, it must enter so that the rack has a good bearing on the flattened portion of the cylinder. (3) See that the feed arm actuating stud is screwed up as far as the stops allow. (4) See that the cocking -handle is placed securely in the slot, and right forward, before replacing the feed arm. (5) See that the feed arm is over to the right before replacing the body cover. 5.---DETAIL OF STRIPPING COMPONENT PARTS . Trigger Group : Using a No. 4 punchDrive out the sear axis pin. Remove the sear. Drive out the trigger axis pin. Removethetrigger. Take out the plunger and spring. Drive out the butt catch fixing pin. Remove the butt catch and spring. To assemble : Reverse the order and processes given above, taking care that the pins do not protrude into the grooves. NOTE.—The trigger group should be stripped only by students in training as Instructors or Armourers . Pinion Casing : Raise the pinion pawl and ease down tension of the return spring. This will cause the tension screw to come away from the shoulders on the pinion casing. Remove the tension screw. Remove the pinion from the casing. Separate the return spring casing from the pinion (pressing out the opposite side of the hub with the point of a bullet, if necessary). Remove the hub . To assemble : Replace the hub, making sure that the turned-in edge of the return spring is over the rounded edge of the slot. Replace the spring casing in the pinion, taking care that the projection on the rim of the former is in the recess provided for it in the latter. Replace the pinion in the pinion casing, taking care that the circular projection round its hub is in the shallow depression made for it in the pinion casing. Screw in the tension screw until it is nearly home, then, holding the screw in line with the shoulders, rotate the pinion until the tension screw is drawn into its seating. NOTE. If the spring is broken, in order to remove the tension screw, it may be necessary to release the pinion pawl and unwind the return spring, at the same time tapping the tail of the tension screw 15 Body Cover : (a) To remove the