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M24 SNIPER WEAPON SYSTEMThe M24 SWS (Figure D1) is a 7.62mm, boltaction, sixround repeating rifle, with one round in the chamber and five in the magazine. This weapon has three sights: iron sights, an M3A daysight, and an AN/PVS10 sniper night scope (SNS).

Figure D1. M24 Sniper Weapon System.Components and OperationTo effectively operate the M24 SWS, the sniper must understand its components and how they work, and he must be able to maintain and repair them.NOTE:See Appendix J for maintenance and repair.

Safety SelectorThe safety selector (Figure D2) is located on the right rear side of the receiver. When properly engaged, the safety selector, labeled "S", protects against negligent discharge.To engage the safety selector, place it in the SAFE position, marked "S". To disengage the safety selector, place it in the FIRE position, marked "F".CAUTIONAlways place the safety selector in the SAFE position before handling, loading, or unloading the weapon; place the safety selector in the FIRE position only when you are ready to fire the rifle and your sights are on the target. Failure to do so can result in accidental firing of the weapon.

Figure D2. Safety selector.Clearing ProceduresTo clear the weapon1. Place the safety selector in the SAFE position.CAUTIONIf the weapon will not move to the SAFE position, perform the following steps with extra caution.2. Lift the bolt handle fully, and pull to the rear.NOTE:Place the safety selector in the SAFE position if unable to in Step 1.3. Inspect the chamber and magazine for rounds.NOTE:If a round is in the magazine, press the floorplate latch (Figure D-5), and the round will drop out of the magazine. Then, close the floorplate.4. The weapon is clear.Bolt AssemblyThe bolt assembly locks the cartridge into the chamber and extracts the cartridge from the chamber.Removing the Bolt from the ReceiverTo remove the bolt from the receiver1. Release the internal magazine.2. Place the safety selector in the SAFE position.3. Raise the bolt handle.4. Pull it back until it stops.5. Push the bolt stop release (Figure D3).6. Pull the bolt from the receiver.

Figure D3. Bolt stop release.Replacing the BoltTo replace the bolt1. Ensure that the safety selector is in the SAFE position.2. Align the lugs on the bolt assembly with the receiver (Figure D4).3. Slide the bolt all the way into the receiver.4. Push the bolt handle down.

Figure D4. Alignment of M24 SWS bolt.

Trigger AssemblyThe trigger is adjusted at the factory for a 2.5-pound nominal trigger pull force. Using the 1/16-inch hex key provided in the deployment kit, the sniper can adjust the pull force to any pull force between 2 and 8 pounds. To do so, turn the adjusting screw (Figure D-5) clockwise to increase trigger pull, and counterclockwise to decrease it.WARNINGNever remove the trigger mechanism or adjust the trigger assembly, except as described.

Figure D5. Adjustment of M24 SWS trigger pullStockThe M24 SWS stock has a butt plate that adjusts for length of pull.AdjustmentTo adjust the M24 SWS stock (Figure D6)1. Turn the thin wheel on the stock counterclockwise (away from the thick wheel) to allow for adjustment.2. Turn the thick wheel on the stock Clockwise to lengthen the stock.Counterclockwise to shorten the stock.3. Turn the thin wheel clockwise (against the thick wheel) to lock the stock in place.

Figure D6. Adjustment of stock.

SlingThe sling binds the parts of the body used in aiming into a rigid bone brace, enabling the sniper to hold the weapon steady without muscular effort. When properly adjusted, the sling permits part of the recoil of the rifle to be absorbed by the nonfiring arm and hand, removing recoil from the firing shoulder.The sling consists of two different lengths of leather straps joined together by a metal D ring (Figure D-7). The longer strap is connected to the sling swivel on the rear stud on the buttstock of the rifle. The shorter strap is attached to the sling swivel on the forearm of the rifle.

Figure D7. Sling.AdjustmentThere are two leather loops on the long strap, known as keepers. The keepers are used to adjust the tension on the sling. The frogs are hooks that are used to adjust the length of the sling.To adjust the sling1. Ensure that the sling is only attached to the front sling swivel.2. Hook the twopronged frog at one end of the long strap into whichever pair of holes (on the same strap) causes the metal Dring to align with the comb of the stock (Figure D8).

Figure D8. Adjustment of M24 SWS sling.3. After adjusting the length of the sling, place the weapon on your firing hip and support the weapon with your firing arm. Turn the sling 90 degrees away from yourself. Insert your nonfiring arm into the loop, and then into the strap.4. Slide the loop in the large section of the short sling, up your nonfiring arm to just below the armpit (left, Figure D9).5. Slide both leather keepers down the sling until they bind the loop snugly around the nonfiring arm.6. Move your nonfiring hand inside the sling, between the sling and the rifle. With the same hand, grasp the weapon just behind the front sling swivel, and force the weapon out and away from yourself (right, Figure D9).7. With your firing hand, pull the butt of the weapon into the pocket of your shoulder. Grasp the weapon at the small of the stock, and begin the aiming process.

Figure D9. Proper placement of the sling.M3A ScopeThe M3A scope enables the sniper to see a magnified image of the target and the crosshairs of the weapon with identical sharpness, which helps the sniper identify and engage the target. The lenses of the scope are coated with a thin material that reduces reflection.MountingThe M3A scope mount (Figure D10) has a baseplate with four screws, a pair of scope rings, and two mounting ring nuts.

Figure D10. M3A scope.To mount M3A scopeNOTE:The iron sights are removed for scope use.1. Mount the baseplate by screwing the four baseplate screws through it and into the top of the receiver. The screws must not protrude into the receiver and interrupt the functioning of the bolt.2. Mount the scope rings. Each pair of scope rings has an upper and a lower ring half and four screws. The M3A scope has two sets of mounting slots. Pick the set that gives you the best eye relief.NOTE:Adjust the eye relief until you can see the full field of view. The average distance is 3 to 3 1/2 inches. Once you have chosen a set of slots, use the same set again in the future to maintain the zero.3. Lubricate the threads of each mounting ring nut.4. Ensure that each mounting ring nut and claw moves smoothly.5. Remove any burrs or foreign matter from the ring nuts and claws.6. Mount the sight and rings to the base.7. Ensure that the mounting surface is free of dirt, oil, or grease.8. Set each ringbolt spine into the selected mounting slot.9. Slide the rear mount claw against the base, and fingertighten the mounting ring nut.NOTE:If the scope needs adjustment, loosen each mounting ring nut, and align the ringbolts with the other set of slots on the base. Repeat Steps 8 and 9.10. Slide the front mount claw against the base, and fingertighten the mounting ring nut.11. Use the Thandled torque wrench, which is preset to 65 inchpounds, to tighten the front and rear mounting ring nuts.AdjustmentThe scope adjustment dials are under the adjustment dust cover. After mounting the M3A scope, the sniper can adjust for elevation, windage, and focus (Figure D-11). He can also adjust the eyepiece (Figure D-12).

Figure D11. Adjustment of focus, elevation, and windage.ElevationThe elevation adjustment dial is located on top of the scope barrel. The dial is indexed from 1 to 10. Each click of the elevation dial equals 1 MOA, and each numbered index mark represents 100 meters.WindageThe windage adjustment dial is located on the right side of the scope barrel. Turning the dial in the indicated direction moves the point of impact in that direction. Each click on the windage dial equals 1/2 MOA.FocusThe focus adjustment dial is located on the left side of the scope barrel. The dial has limiting stops. To adjust the focus adjustment dialFor a close target, rotate the dial to the largest dot, and focus out from there.For a distant target, rotate the dial to the infinity symbol (), and focus in from there.EyepieceTo focus the eyepiece (Figure D-12)1. Grasp the eyepiece, and back it away from the lock ring.NOTE:The lock ring loosens automatically, so you need no tools.2. Turn the eyepiece several turns to move it at least 1/8 inch. This is the smallest change that will affect the focus.3. Look through the scope at the sky or a blank wall to ensure that the reticle looks sharp.4. Lock the lock ring.

Figure D12. Adjustment of eyepiece.Mil-Dot Technique of Range DeterminationWhen using the M3A scope, the sniper uses the mil dots on the reticle to determine the range to the target. The lines in the duplexstyle, mil-dot reticle (Figure D13) have thick sections near the outside of the ring and thin sections on the inside. Superimposed on the thin center of each radia is a series of dots, four to each side of the center of the reticle and four above and below the center. These dots divide the four radia into six equal sections, 1 mil apart, and 1 mil from the center and the start of the thick portion of the reticle. This lets the sniper closely estimate target range, assuming that he sees an object of known size (height or width) in the field of view. For example, at 500 meters, a 6-foot human target is 3.65 mils.

Figure D13. Mil-dot reticle.ZeroThe sniper zeroes the M3A scope on a knowndistance range (preferably 900 meters long) with 200yard bullseye targets (NSN SR16920009008204). To zero the M3A scope1. Assume a good, pronesupported position 100 meters from the target.2. Ensure that the "1" on the elevation dial aligns with the elevation index line, and that the "0" on the windage dial aligns with the windage index line.3. Fire three rounds at the center of the target, keeping the same aiming point each time.4. After noting the strike of the third round, triangulate the result.5. Turn the elevation and windage dials to bring the point of aim to the point of impact.Each click on the elevation dial equals 1 MOA. At 100 meters, 1 MOA equals about 1 inch.Each click on the windage dial equals 1/2 MOA. At 100 meters, 1/2 MOA equals about 1/2 inch.6. Once you center a shot group, loosen the hex head screws on the elevation and windage dials. If needed, turn the elevation dial to index line "1" and the windage dial to index line "0," and then tighten the hex head screws.NOTE:After zeroing at 100 meters and calibrating the dial, confirm the zero by firing and recording sight settings through 900 meters, at 100meter increments.FieldExpedient Confirmation of ZeroCircumstances, such as dropping a weapon or extreme climatic changes can force the sniper to confirm zero in the field. There are two field-expedient methods to confirm zero:25yard or 900inch method.Observation of impact method.25Yard or 900Inch MethodTo perform the 25yard or 900inch method1. Dial the scope to 300 meters for elevation and 0 for windage.2. Aim and fire at a target at a distance of 25 yards.3. Adjust the scope until rounds impact 5/8 of an inch above the point of aim.4. To confirm, set elevation to 500 meters. The rounds should impact 1/4 inches above the point of aim.Observation of Impact MethodWhen a known distance range is unavailable, the sniper should perform the observation of impact method. To perform this method1. Locate a target where the observer can see the impact of rounds clearly.2. Determine the exact range to the target.3. Dial in the appropriate range, and fire.4. Watch theimpact of the round; the observer gives sight adjustments until round hits the point of aim.RemovalHe can easily remove and replace the scope with less than 1/2 MOA change in zero. However, he should try to leave it on the rifle.StorageThe M3A scope is a delicate instrument that must be handled with care. Dirt, rough handling, or abuse of any optical equipment can affect accuracy and function. To properly store the M3A scope, consider the following:When not in use, place the scope in its case, with all lenses capped.Keep the lenses free of oil and grease. Avoid touching the lenses with your fingers, because body oil and perspiration can damage them. To remove oil or grease, apply a drop of lenscleaning fluid or rubbing alcohol on a lens tissue. Use a circular motion to wipe each lens carefully, beginning at the center, and moving outward. Dry the lenses using a clean lens tissue. If you lack these supplies, breathe heavily on the glass and wipe it with a soft, clean cloth.When removing dust and other foreign matter, carefully brush the lenses with a clean camel hair brush.Check and tighten all mounting screws periodically, and always before an operation.Do not disturb the coarse windage adjustment.Do not force the elevation and windage screws or knobs.Keep the scope covered when not in use. The lenses will magnify and concentrate sunlight into a pinpoint of intense heat, which would fall on the milscale reticle. This could melt the mil dots and damage the scope internally.Avoid dropping the scope or striking it with another object. Not only could this affect the zero, it could also permanently damage the scope.In moderate temperatures, remove condensation by placing the sight in a warm place. Avoid the application of concentrated heat, because it can expand and damage the sight. Blot any moisture from the optics with a lens tissue or a soft, dry cloth.Thoroughly clean, dry, and lightly oil the scope after use, because perspiration is salty and can cause rust.Further, different climates require different procedures for maintaining optical equipment:

In extreme coldAvoid letting water condense or oil congeal on the sight. In cold temperatures, oil thickens and causes sluggish operation or failure. Focusing parts are vulnerable to oil seepage and their function would be greatly affected if those oils froze.Breathing produces frost, which can accumulate on the sight. Clean it off with lens tissues preferably dampened lightly with alcohol.In hot, humid temperaturesKeep the caps on the scope when not using it.If moisture or fungus develops on the inside of the scope, replace the scope.In desert conditions, protect the scope from direct sunlight.When operating in salt water conditionsProtect the scope from direct sunlight.Inspect, clean, and lightly oil the scope regularly to prevent rust and corrosion.AN/PVS10 sniper night scopeThe AN/PVS10 sniper night scope (SNS) is an integrated daysight and nightsight for the M24 SWS. This scope magnifies the image of the target to improve the sniper's aim. The fixed mount, mounting clamps, and nuts allow the sniper to detach and reattach the scope easily, while maintaining accuracy of the scope. The main components of this AN/PVS10 SNS include the objective lens assembly, relay optics for both day and night viewing channels, and an eyepiece assembly.NOTE:An identification plate on the bottom of the scope gives the serial number and other information needed for maintenance and hand receipt purposes. The 3inch (76mm) eye relief protects the eye from recoil injury.Figure D14 shows the following components of the AN/PVS10 SNS:1. Battery CapThe battery cap attaches to the housing with a thumbscrew. It seals to keep the battery compartment waterproof.2. Carrying CaseThe carrying case transports and protects the scope and accessories.3. Technical ManualTM 11585530312&P provides unit maintenance instructions.4. Light Interference FilterThe light interference filter (LIF) has a filter cell, filter, retainer, and Oring. It protects the sniper from eye injury and the image intensifier tube from battlefield lasers. It is installed in front of the objective lens.5. Objective Lens CapThis cap protects the objective lens and acts as a sunshade when the lens cap is in the open position. A 1/8inch pinhole in the center of the cap lets the sniper operate the night channel of the scope in daylight.6. BatteriesThe AN/PVS10 SNS operates on either two AA alkaline batteries or two 1.5volt AA lithium batteries. The sniper should save the lithium batteries for extremely cold conditions, when the alkaline batteries will fail to function.7. Lens PaperThe sniper uses lens paper to clean the lens surfaces.8. Shipping and Storage CaseThe shipping and storage case protects the AN/PVS10 SNS. It has upper and lower inserts and a nameplate.9. Light Interference Filter BagThe LIF bag protects the filter when not in use.10. O-RingsThese rings, located below the dial dust covers, protect the dial from moisture.11. Dial Dust CoversThese covers protect the windage and elevation dials.12. EyeguardThe eyeguard has a molded rubber eyecup and an adapter ring. It protects the eye from recoil, keeps the imageintensifier tube from illuminating the sniper's face, and protects the eyepiece optics.13. Protective CapThis cap protects the eyepiece lens in the case and when the eyeguard is not used.14. SunshadeThis shade reduces the reflection of the sun off the objective lens.Not depicted is the cutoff sensor. The cutoff sensor points upward from the top of the housing. This sensor conserves battery life and protects the tube from damage in case the scope is left in NIGHT mode in daylight. When it senses light levels greater than 4 foot-candles for more than 70 seconds, it shuts off automatically and stays off until the sniper presses the TUBE ON/OFF switch.

Figure D14. AN/PVS10 sniper night scope.

The lines in the duplexstyle, mildot reticle (Figure D15) each have a thick section near the outside of the ring and a thinner section near the center. An etchedglass reticle is located on an image plane shared by the eyepiece and the two relays. In NIGHT mode, the reticle is illuminated, and the objective lens assembly focuses incoming light on the imageintensifier tube. In DAY mode, the movable mirror remains up in front of the image tube. This feature protects the image tube from exposure to direct sunlight. In NIGHT mode, the mirror remains down and away from the daymode optical path, preventing reticle illumination from projecting back through the objective lens. The image tube has automatic brightness control and manual gain control. The daynight relays send the image to the reticle.

Figure D15. Reticle and location of low battery indicator.