a. Maintenance and repair of the rifles covered in this manual, and their appendages and accessories, consists primarily of replacement of worn or broken parts. These parts are listed in SNL B-3, and symbols are used to indicate whether they are supplied for replacement purposes to the using arms, ordnance maintenance companies, field service shops, or other ordnance establishments. For detailed instructions on disassembly and assembly of this materiel, refer to section II of this manual b. Where parts, assemblies, or parts of assemblies are broken or so worn as to render them unserviceable, they must be replaced from stock Often only parts of assemblies will be worn or broken; where it takes more time to remove the serviceable parts from the assembly than the parts are worth, the assembly should be scrapped.
e. In general, maintenance operations are of a first-aid nature. They are performed with only the limited tool facilities afforded by repair trucks, by semipermanent shops at posts and camps, or by an inspector while making a regular inspection- The decision as to the work to be performed by the available personnel with the facilities at hand is left to the discretion of the ordnance officer in charge.
d. The telescopic sight furnished with the Rifle M1903A4 and covered in this manual is issued as a complete assembly. If sight is damaged or cannot be adjusted for serviceability as explained in this manual, it must be replaced with a complete sight assembly and the unserviceable sight returned to a base shop or the factory for repair or disposition. The mount base, mount rings, shims and component screws are replaceable.
a. General Tools. General tools used in maintenance and repair are listed in SNL B-3 as company accessories for the rifle. They are also listed in SNL B-20 and are carried on the small arms repair truck. These tools require no explanation of their use.
b. Special Tools. Special tools used for maintenance and repair are listed and shown in SNL B-20 and are carried on the small arms repair truck. A general description of these tools is given below:
(1) DEVICE, Tightening, Front Sight, C3826. This device is used for tightening the front sight movable stud when it is loose in the fixed stud (Rifles MI903 and M1903A1). It consists of a pair of tweezers for squeezing together the two sides of the undercut slot on the fixed stud, and a dovetail tapered gage A13220 which, when inserted in the slot of the fixed stud, serves as a stop for the tweezers at the desired point For details of the use of this device, see paragraph 46 b (3).
(2 ) ROD, Drill. The drill rod is a round rod 0.281 inch in diameter and 2,5 feet long. It is provided for removing cleaning rods, cut patches, etc., which may become stuck in the bore of the rifle.
(3) WRENCH, Windage Screw, SA2822. The windage screw wrench is in the form of a crank, and has a wooden handle. The socket can be adjusted to fit tightly on the knob of the windage screw. It is used for turning the windage screw when disassembling and assembling the rear sight movable base (Rifles M1903 and M1903A1).
a. Bolt Assembly. Burs on lugs and camming surfaces should be removed with a sharpening stone and finished with CLOTH, crocus, care being taken not to remove too much metaL If the striker hole or the face of the bolt is worn or eroded to the extent that it allows the primer of the cartridge to blow back, or tend to blow back, the bolt assembly should be replaced. If the extractor collar is deformed to the extent of affecting the action of the extractor, the bolt assembly should be replaced.
b. Extractor. If the extractor h weak or the hook is broken, it should be replaced.
c. Firing Pin Assembly. Burs on cams, sear notch, and safety lock grooves should be removed with a sharpening stone and finished with CLOTH, crocus. Care should be taken not to deform the sharp edge of the sear notch.
d. Mainspring. If mainspring is weak or will not function properly, it should be replaced.
e. Striker, If striker point is worn or broken or if joint tips are broken, it should be replaced-
f. Bolt Sleeve Assembly. If threads or safety lock plunger groove is deformed, the sleeve should be replaced. Burs on sleeve lock should be removed with a sharpening stone. A weak lock spring should be replaced g. Safety Lock Assembly. If safety lock assembly is damaged so that it will not function properly, it should be replaced.
b. Working in Stiff Bolt.
(1) When the bolt fails to function smoothly, it may be worked in by the proper application of COMPOUND, valve grinding, fine (SNL K-2), to the extracting cam and cocking cam, and OIL, lubricating, preservative, special (SNL K-l), to the extractor collar as described insteps (2), (3), and (4), below.
(2) Smoothing Extracting Cam (fig. 63). Strip down rifle to receiver, barrel, and bolt Remove firing pin group from bolt Place receiver with barrel attached in bench vise, using either wood or leather between vise jaws to prevent damage to rifle. Muzzle and chamber of the barrel should be plugged with CLOTH, wiping, and muzzle end of barrel should be slightly elevated in vise. Apply a small quantity of COMPOUND, valve grinding, fine, to the primary extracting cam situated at the left rear end of receiver (fig- 28). Enter bolt in receiver. Apply COMPOUND, valve grinding, fine, to extracting cam of bolt (fig. 17). Grasp handle of bolt in palm of right hand and, with a forward pressure upon bolt handle, rotate handle rapidly back and forth, at the same time maintaining enough forward pressure upon bolt to keep cam surfaces of receiver and bolt in contact. Continue this operation until a smooth, regular surface is obtained upon both cam surfaces. Wipe dry and thoroughly clean all traces of COMPOUND, valve grinding, fine, from all surfaces of bolt and receiver.
(3) Smoothing Cocking Cam (fig. 64), Reassemble firing pin group to bolt. Apply a small quantity of the COMPOUND, valve grinding, fine, to cocking cam surfaces of bolt (fig. 18) and cocking piece (fig. 24)» Enter bolt in receiver. Close bolt. Be sure that trigger and sear are removed from receiver. Grasp bolt handle in
Figura 63 — Smoothing Extracting Com
Figura 63 — Smoothing Extracting Com
RA Pt> 10873
Figure 64 — Smoothing Cocking Cam
RA Pt> 10873
Figure 64 — Smoothing Cocking Cam
brass plug brass plug
palm Qf right hand, and with a slight forward pressure upon bolt handle, rapidly cock and release firing pin by rotating bolt handle up and down. Continue this operation until a satisfactory smooth surface is obtained. Clean, dry, and thoroughly wash all traces of the COMPOUND, valve grinding, fine, from all surfaces, as it is very important that no trace remain to cause undue wear and injury to the mechanism.
(4) Freeing Extractor Collar (fig. 65). Provide a pair of special hardwood jaws with a recess to engage ears of extractor collar and clearance for body of extractor collar (figs. 17 and 18), Place jaws in vise, inserting bolt so that ears on extractor collar fall in dogging slot provided Close vise with jaws encircling body of bolt, allowing bolt to be rotated freely while the collar is held stationary. A Vi-inch hole should be drilled in the hardwood vise jaws to allow for insertion of the lubricating material. Prepare a soft brass plug, one end turned and threaded to screw into rear end of bolt, the other end, either square or round, to be gripped by any suitable rotating member, preferably a bit brace or breast drill. With brass plug screwed into bolt and gripped by jaws of bit brace or breast drill, rapidly rotate bolt, applying freely OIL, lubricating, preservative, special, only, until extractor collar is entirely free. Clean, wash, and dry bolt
CAUTION: Special precautions should be taken to remove completely all traces of the COMPOUND, valve grinding, fine, from the rifle. All washing and cleansing operations should be performed with the barrel held in a vertical position,
(1) Some bolts for the M1903 and M1903A1 Rifles do not have notches for the bolt stop pin (fig. 16). These notches were purposely omitted so that the bolt stop assembly (fig. 56) could be eliminated. Whenever a new bolt, which does not have notches, is installed in a Rifle M1903 or M1903A1, it is necessary to remove and discard the bolt stop assembly.
(2) To remove the bolt stop assembly, disassemble the barrel and receiver group from the stock assembly. There is a small hole in one end of the bolt stop spring. Place the end of a pointed instrument in the hole and extract the bolt stop assembly (par. 17 e).
NOTE: The bolt stop assembly is located in the under side of the receiver, directly to the rear of the magazine opening (fig. 56)- The bolt stop pin notches in the bolt, are located in the left side of the upper lug on the forward end of the bolt (fig. 16).
44. FLOOR PLATE GROUP (RIFLES M1903 AND M1903A1), a. Floor Plate and Follower. Burs on floor plate tenons and follower should be removed with a sharpening stone.
b. If magazine spring is weak or damaged, it should be replaced.
(1) If the stock is split, it should be replaced. Scratches and bruises that do not weaken the stock can be removed or smoothed with a half-round smooth file, and finished with PAPER, flint, class B, No. 00.
(a) It is frequently found that stocks are distorted due to moisture, a condition which makes their assembly to barrel and receiver assemblies difficult The stock should fit the rifle snugly at only two points, namely, in the immediate vicinity of the front and rear guard screws. The recoil lug of the receiver fits into a mortise in the stock, and the front guard screw which is screwed into the lug holds the stock firmly between the guard and the forward under surface of the receiver. The portion of the stock forward of this point is so designed that the barrel floats freely in it without actually being supported by it and sufficient clearance is allowed so that it does not bind when the barrel becomes heated- The barrel bed or the extreme forward end of the stock upon which the upper (or bayonet stud) band is assembled is the most critical point "Bound barrels" occur frequently. A bound barrel does not have room for expansion when heated during firing and may become warped, bulged, or twisted,
(b) If this condition is caused by too much wood on the stock, remove upper band screw and slip off the upper band (Rifles M1903 and M1903A1). Polish off that portion of the stock on which the upper band seats with PAPER, flint, class B, No, 00. After a little wood has been removed, a small file should be used to square up the shoulder for the upper band As the work progresses, the upper band should be put in place without the insertion of the upper band screw and the barrel tested for looseness by a vertical motion. The foregoing operation should be repeated until there is a perceptible movement of the barrel when the upper band is assembled on the gun. It sometimes becomes necessary to remove some stock from the front tenon of the hand guard. This stock can be removed with PAPER, flint, class B, No. 00,
(c) If the condition is caused by the upper band screw being too far from the barrel bed, remove the upper band screw, slip off the upper band, and plug up the upper band screw hole. Replace upper band and establish center of new hole for upper band screw so that there will be a perceptible movement of the barrel when the upper band is assembled on the gun. Drill out the new hole and assemble upper band and upper band screw in place,
(d) If both of above methods fail, the barrel bed should be gouged out very slightly with a rasp, file, or similar tool until the barrel floats satisfactorily. The float in the barrel may be checked by placing thumb on under side of barrel and forefinger on top of upper band and exerting pressure on the barrel. The barrel should spring away from stock when a pressure of approximately 4 pounds is exerted,
NOTE: The same general procedure can be followed for the bayonet stud band, stacking swivel band, and barrel guard of the Rifles M1903A3 and M1903A4.
(3) Magazine Well. If trigger guard (or trigger guard magazine) will not assemble properly with barrel and receiver assembly, a wood rasp is used to remove the interference. This must be done carefully to avoid removing too much wood. It is necessarily a cut and try operation and should be done only by personnel familiar with this type of work, b. Upper Band Assembly (RifleB M1903 and M1903A1). Burs on bayonet stud should be removed with a sharpening stone. Burs on screwheads should be removed with a fine file. If threads are burred, they should be chased with a die. If stacking swivel is bent, it can probably be straightened by placing it in a vise with copper jaws and bending it back into shapeT using a hammer, wrench, or cold chisel. If it cannot be bent back into shape, or if it is broken, it should be replaced.
NOTE: The same general procedure can be followed for the bayo net stud band of the Rifles M1903A3 and M1903A4. If the stacking swivel is bent and cannot be easily straightened without disassembling from the band, the stacking swivel band assembly should be replaced c. Lower Band Assembly» Burs on screw threads should be removed with a die, A broken or bent swivel should be treated as described in subparagraph b, above. (The lower band screw of the Rifles M1903A3 and MI903A4 is expanded at the end to prevent removal. If screw, band, or swivel are damaged, the assembly should be replaced.)
d- Lower Band Spring. A damaged lower band spring should be replaced.
e. Hand Guard or Barrel Guard Aaeembly. A split hand guard or barrel guard should be replaced.
f. Butt Swivel Assembly. Burs on screwheads should be removed with a fine file. Loose screws should be tightened. A broken or bent swivel should be treated as in subparagraph b, above. (If the swivel on Rifles M1903A3 and M1903A4 is damaged, the assembly should be replaced)
g. Butt Plate Assembly. Burs on butt plate and screwheads should be removed with a fine file. Loose screws should be tightened A weak or broken butt plate spring should be replaced (Rifles M1903 and M1903A1). If the butt plate trap spring of Rifles M1903A3 and M1903A4 is weak or broken, the butt plate assembly should be replaced h. Trigger Guard Group (Rifles M1903 and M1903A1). Burs on screwheads should be removed with a fine file. Damaged threads should be chased with a die. A broken floor plate catch or weak spring should be replaced i. Trigger Guard Magazine Group (Rifles M1903A3 and M1903A4). Burs on screwheads should be removed with a fine file. Damaged threads should be chased with a die. If threads are worn so as to make screws loose, screws should be replaced
a. Rust should be removed from the outside of the barrel by rubbing with a CLOTH, wiping in OIL, lubricating, preservative, special If this is not sufficient, lightly use CLOTH, crocus, taking care not to produce a shiny surface. Burs should be removed with a sharpening stone.
b. Front Sight Group (Rifles M1903 and M1903A1) (fig. 51).
(1) If front sight is bent, broken, or shiny, it should be replaced If movable stud is damaged, it should be replaced The fixed stud is supplied as a component of the barrel assembly.
NOTE: In an emergency, shine may be eliminated temporarily in a manner similar to that prescribed for the cut-off in NOTE, paragraph 47 b.
(2) To repair a loose front sight fixed stud, drive out fixed stud pin and remove fixed stud- Slightly peen the top surface of the spline on the barrel The peening should be just enough to make a snug fit between the slot in the fixed stud and the spline when assembled. Reassemble fixed stud and fixed stud pin.
(3) To tighten a loose movable stud in fixed stud, the front sight tightening device C3826 is the standard tool for use in the field. To use the device, the front sight screw and movable stud are removed and the dovetailed gage A13220 inserted in place of the movable stud, being pushed in by hand until tight. It is then withdrawn sufficiently to allow the fixed stud to be closed to the correct dimension. It will be noted in this connection that the dovetailed gage acts as a stop in closing the fixed stud. The tweezers are then applied and the fixed stud closed to its original size and shape to fit the movable studL The amount the gage is withdrawn depends on the amount the fixed stud is sprung. This can be estimated very accurately, after a little practice, by noting the amount of looseness of the sight before attempting to use the device. Replace movable stud and screw in front sight screw.
(4) When new movable studs are installed, it may be found necessary to drill a hole for the front sight screw, as considerable quantities of undrilled movable studs of early manufacture are still in stock. To drill this hole proceed as follows: Locate the movable stud centrally in the fixed stud With the muzzle of the rifle held firmly in a vise, copper jaws being used, and the butt of the rifle supported on the bench, drill a hole 0.0935 inch in diameter in the movable stud approximately inch deep, using the hole already drilled in the fixed stud as a jig or guide. Care must be taken not to bur the threads in the fixed stud. Keep the drill well oiled Put little pressure on the drill until it has been well started or the drill may be broken or the movable stud moved. After the hole has been drilled, it should be reamed out with a 0.094-inch reamer, care being taken not to put too much weight on the reamer as it is inclined to wedge and break. It may be possible that the threads for the front sight screw are burred and should be cleaned out with the 0.117-inch tap; this can be determined by screwing the front sight screw into the fixed stud.
c. Front Sighl Group, Rifle M1903A3 (fig. 54). In this rifle, the base of the front sight which corresponds to the fixed stud in subparagraph b, above, is held on the barrel by a key seated in a longitudinal keyway, and a pin passing through the sight base and a groove in the key when assembled. If the key is worn, it should be replaced.
If keyway in barrel is worn it may be peened in slightly at the top edges or at the ends. There should be no movement of the key in the keyway when assembled If the front sight (blade) is loose, bent, broken, or shiny, it should be replaced, using same height of sight as the one removed (NOTE, subpar. b (1), above). (There are several heights of front sight used, as listed in SNL B-3.)
d. Rear Sight Assembly (Rifles M1903 and M1903A1).
(1) It is important that the front and rear lips of the rear sight movable base fit snugly in the undercuts of the fixed base. This is necessary so that the rear sight leaf when raised does not rock from side to side in a manner that may cause errors in sighting from round to round, and so that the movable base will remain in the proper position when "windage" is taken by the firer. Looseness of the movable base can usually be corrected by tapping either one or both of the overhanging lugs of the fixed base (ordinarily the rear one), using a bronze block or a drift so that the lug is bent slightly. If these undercuts of the fixed base are burred or bind the movable base too tightly, the movable base should be removed and the shaving tools 24-17-9C and 24-17-9D for the front and rear ends of the rear sight fixed base, used (when available) to shave the surface to a proper fit
(2) The windage screw is handled as an assembly, for when the spring is weakened the threads are generally worn also, and it is practical to replace the entire assembly.
(3) A bent rear sight slide is corrected by using a face plate or other flat surface, a set with a face approximately 7/16 by % inch, and a small hammer. The straightness is gaged by the use of a scale. The slide should be very slightly concave.
(4) A bent rear sight slide cap, pin, binding screw, rear sight leaf, or weak base spring is corrected by replacing the proper part or parts. The fixed base is supplied as a component of the barrel assembly,
47, RECEIVER GROUP.
a. Burs on bearing surfaces and cams of receiver should be removed with a sharpening stone, taking care not to remove too much metal, nor to change the angle of the face.
b. Cul-off Assembly. A broken cut-off, spring, plunger, or spindle should be replaced. If cut-off screw will not retain the spindle, it should be replaced. If the under side of the lever portion of the cutoff where the word "ON" is stamped (fig» 23) is shiny, the cut-off should be replaced, when possible, by one with an oxide black finish. When rifles are being overhauled and this part is given an oxide black finish it should be left black, and not repolished All cut-off levers used for replacement and on hand should be given a black finish to eliminate this shiny finish.
NOTE: In an emergency, shine may be eliminated temporarily by the application of PAINT, black, flat, to the shiny surface. The surface should be thoroughly cleaned to remove all oil and dirt before applying paint Such painting should be considered only as a temporary correction as the paint will soon wear off.
c. Bolt Stop Assembly. If parts are broken or spring is weak, assembly should be replaced (Some Rifles M1903 and MI903AI are without the bolt stop assembly, as explained in paragraph 43 i.)
d. Ejector. Burs on the point of the ejector should be removed with a sharpening stone.
e. Sear. Burs on nose of sear should be removed with a sharpening stone, taking care to remove as little metal as possible and to retain the proper angle of the faces. If nose is worn so that it will not hold in sear notch of firing pin, sear should be replaced. A weak or damaged spring should be replaced If the sear pin is worn sufficiently to allow side play, it should be replaced f- Trigger.
(1) Burs on bearing and heel of trigger should be removed with a sharpening stone, care being taken not to remove too much metal. A loose trigger pin, especially if it allows side play, should be replaced
(2) When creep, as defined in paragraph 28 c (4) is found in a trigger, or when the trigger weight does not fall within the prescribed limits, examine the sear" nose and sear notch for burs or rough surfaces (fig. 66), All burs should be removed by stoning and all surfaces which are not perfectly smooth should be polished by stoning. Sharp corners and edges must not be rounded 08. Should this procedure fail to produce the desired degree of smoothness in the action or the desired correction in trigger weight, the heel of the trigger and the point at which it comes in contact with the receiver should be inspected and any roughness removed by stoning. Should the action still be faulty, it will be necessary to interchange the parts until a combination of cocking piece, sear and sear spring, trigger, and mainspring is found which will correct the difficulty. The probable importance of these various parts in the perfection of the trigger pull is in the order given. A number of parts should be tried in their various combinations until a satisfactory pull is obtained The shapes of the cocking piece sear notch and sear nose and the strength of the sear spring should always be such that the sear invariably rises to its full height and the trigger returns to its forward position on a cocked rifle when the trigger is released g. Rear Slghl Assembly, Rifle M1903A3 (fig. 57). If aperture slide, spring, or screw are damaged so as to prevent proper operation or retention of the slide, the damaged parts should be replaced
If the windage index knob screw or spring are damaged, they should be replaced. If other parts of the sight assembly other than springs or screws are damaged, the rear sight assembly should be replaced. Burs on threads of windage yoke screw may be removed with a die.
NOTE: Improper assembly of the slide aperture spring may cause the slide aperture to operate poorly, as explained in paragraph 33 g, h. Telescopic Sight Group, Rifle M19Q3A4.
(1) The Telescopic Sight M73B1 (Weaver No. 330 C) is issued as a complete assembly and aside from cleaning, oiling, and adjustments prescribed in paragraphs 55, 56, 57, 58, and 60, no repairs can be made in the field. If the sight becomes unserviceable it should be replaced by a new sight assembly and the damaged one forwarded to a base shop (or the factory) for repair or disposition.
(2) The mount base and mount rings, together with their component screws and shims, are replaceable. When such parts are replaced, the sight should be checked for alinement and level, as prescribed in paragraphs 57 and 58.
(3) If the mounting recess in the front end of the mount base becomes burred, it may be smoothed by using a small file or sharpening stone. If the recess becomes enlarged to the extent that the front mount ring has play, the base should be replaced (Such play may result from a worn mounting lug on the front mount ring.)
(4) If the mounting lug on the front mount ring becomes burred it may be smoothed with a small file or sharpening stone. When wear is present to the extent that there is play between ring and base, it may sometimes be tightened by lightly peening the ends of the lug towards the ring. If such peening does not take up the slack, the ring should be replaced. (Such looseness may be due to wear in the mounting recess in the base.) Before peening the lug, the front mount ring should be removed from the sight and mounted on a metal rod of the same diameter as the sight tube, to prevent deformation of the ring when peening. Never attempt to peen the ring while mounted on the sight.
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