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US RIFLE M16A1 CAL. 5.56 MM

 

 

I.            CHARACTERISTICS

    The US Rifle M16A1 Cal. 5.56 mm is a shoulder weapon that is air-cooled, gas operated and magazine-fed. It is designed for either a semi-automatic or fully-automatic fire through the use of a selector lever. In addition, it has the following characteristics.

              a. The rifle is equipped with a flash compressor that also serves as a stationary piston that permits the launching of rifle grenades without the use of supplementary attachments.

             b. Its barrel is surrounded by two aluminum-lined fiberglass handguards which serves as a foreman. The handguards are notched to permit air to circulate around the barrel, and further serve as a protector for the gas tube.

             c. The hard rubber pad attached to the butt of the stock reduces partially the effects of recoil.

             d. Its forward assembly located on the right rear of the upper receiver allows the closing of the bolt when this is not done by the force of the action spring.

             e. It has a “clothespin” bipod used in the prone and foxhole positions. The bipod is attached to the barrel directly beneath the front sight between the bayonet lug and the front sling swivel.

             f. The trigger becomes easily adaptable to winter operations. A spring-loaded retaining pin is depressed with a cartridge point to allow ready access to the trigger with arctic mittens.

             g. It is provided with a dust cover to prevent dirt or sand from getting into the rifle. The dust cover should be closed during periods when firing is not anticipated. It opens automatically by the forward or rearward movements of the bolt carrier.

 

II.     GENERAL DATA

 

A. Weight (in pounds)

                    Rifle without magazine and sling …………………………………………….. 6.5 lbs.

        Empty magazine (aluminum)………………………………………… ……….. 0.2 lbs.

        Full magazine (20 rounds)…………………………………………………….. 0.7 lbs.

        Sling, M1………………………………………...………………………………. 0.4 lbs.

        Firing Weight (fully loaded with sling)………………………………. ………. 7.6 lbs.

        Bipod, M3………………………………………………………………. ….…... 0.6 lbs.

        Bipod case…………………………………………………………….. ………. 0.2 lbs.

        Bayonet-knife, M7……………………………………………………. ………. 0.6 lbs.

        Scabbard, M8A1……………………………………………………… ………. 0.3 lbs.

 

B. Lengths (in inches)

                    Rifle with bayonet-knife……………………………………………… ……….. 44.25 in.

        Rifle with flash suppressor………………………………………….... ……….. 39.00 in

        Barrel with flash suppressor…………………………………………………... 21.00 in

        Barrel without flash suppressor……………………………………………….. 2\0.00 in

 

             C. Sights

                        a. Front – adjustable click-type post. Each click equals 2.8 cm. per 100 meters of range.

            b. REAR – adjustable flip-type. Normal range is from 0 – 300 meters. Long range setting (L), 300 – 500 meters. Each notch of the winding drum equals 2.8 cm per 100 meters of range.

                         c. SIGHT RADIUS – 19.75 inches

 

D. Ammunition

                 Caliber 5.56……………………………………………………………………..179 grains

          Projectile………………………………………………………………………... 55 grains

 

             E. Operational Characteristics

                      Muzzle velocity……………………………………………………………..…... 3,150 ft/sec (approx)

          Muzzle energy (at muzzle)…………..………………………………………....1,300 ft-lbs (approx)

          Cyclic rate of fire………………………………………………………………....700-800 rds/min

          Maximum rate of fire

                               Semi-automatic……………………………………………..…………..45 – 65 rds/min

       Automatic…………………………………………………….………….150 – 200 rds/min

        Sustained………………………………………………..………………12 – 15 rds/mi

            Maximum – range…………………………………………….…..……………....2,653 meters

            Maximum effective range……………………………………..…………………460 meters

 

III.    TYPES OF AMMUNITION

                 a. Ball

    b. Tracer

    c. Blank  

 

IV.     CLEARING THE RIFLE

             In handling any weapon, the first impulse is to make it safe by clearing it. To clear the M16A1 rifle, place the butt against the right thigh and observe the following.

                     a. Point the sector level towards safe. If the rifle is not cocked, the sector lever cannot be pointed toward safe. If this is the case, do not cock the weapon; instead, proceed with the next step.

                     b. Remove the magazine by the right hand (the fingers curled around the front of the magazine, the thumb placed on the magazine catch button), apply pressure on the magazine catch button with the thumb, and pull the magazine out of the rifle.

                     c. Lock the bolt open by grasping the charging handle with the thumb and forefinger of the right hand, and pulling to the rear; press the bottom of the bolt catch with the thumb or forefinger of the left hand when the bolt is fully rearward. Allow the bolt to move slowly forward until it engages the bolt catch, and return the charging handle to its forward position.

                     d. Inspect the receiver and chamber by looking through ammunition.

                     e. Check the selector lever to insure that it points toward safe and allow the bolt to move forward by depressing the upper portion of the bolt catch.

 

V.     DISASSEMBLY

               a. Remove the sling and place the rifle on a table or a flat surface with its muzzle to the left.

     b. Keeping the muzzle to the left, turn the weapon on its right side. Use a punch or the end of a cleaning rod (nose of cartridge used only as a last resort in the field) to press the takedown pin (fig. 3-38) until the upper receiver swings free of the lower receiver (fig. 3-39),

                    NOTE:   The takedown pin does not come out of the receiver.

Figure 3-38. Pressing the takedown pin to the right.

 

Figure 3-39. Breaking the upper receiver away from the lower receiver.

 

               c. Again using a punch or the end of a cleaning rod, press the receiver pivot pin (fig. 3-40). Separate the upper and lower receiver groups (fig. 3-41) and place the lower receiver group on the table.

Figure 3-40. Pressing out the receiver pivot pin.

 

Figure 3-41. Upper and lower receiver groups.

                           

                        NOTE:  The receiver pivot pin does not come out of the receiver.

             d. Pick up the upper receiver group; keep the muzzle to the left. Grasp the charging handle, pressing in on the latch, and pull to the rear to withdraw the bolt carrier from the receiver. Grasp the bolt carrier and pull it from the receiver (fig. 3-42). When the bolt carrier is removed, the charging handle will fall free of its groove in the receiver (fig. 3-43). Place the receiver on the table.

 

Figure 3-42. Removing the bolt carrier from the receiver.

 

Figure 3-43. Removing the charging handle.

 

               e. 5. To disassemble the bolt carrier group, press out the firing pin retaining pin by using a driftpin (fig. 3-44). Elevate the front of the bolt carrier and allow the firing pin to drop from its well in the bolt (fig. 3-45). Rotate the bolt until the cam pin is clear of the bolt carrier key and remove the cam pin by rotating it 90 degrees (one-quarter turn) and lifting it out of the well in the bolt and bolt carrier (fig. 3-46). After the cam pin is removed, the bolt can be easily removed from its recess in the bolt carrier (fig. 3-47).

 

Figure 3-44. Pressing out the firing pin retaining pin.

 

Figure 3-45. Removing the firing pin.

 

Figure 3-46. Removing the cam pin.

 

Figure 3-47. Removing the bolt.

 

VI.     ASSEMBLY

                 a. To assemble the bolt carrier group, key up the end to the front, inserting the bolt into the front of the bolt carrier, insuring that the ejector is down to the left. Replace the cam pin into its well and rotate the cam pin 90 degrees (½ turn) to align the bolt and turn until the cam pin is directly beneath the bolt carrier key. Insert the firing pin through the opening of the bolt carrier and sit fully. Insert the firing pin retaining pin (if resistance is encountered, rotate the pin while inserting).

     b. Grasp the upper receiver with the carrying handle up. Place the charging handle into the groove on the top of the upper receiver. The lugs on the charging handle must be seated in their grooves in the receiver. Place the bolt carrier group into the open end of the receiver, insuring that the bolt carrier key is in the slot on the underside of the charging handle and the bolt is forward in the unlocked position. Push forward the bolt carrier group and the charging handle until fully seated.

     c. Place the upper and lower receiver groups together and reset the receiver’s pivot pin.

    d. Cock the hammer and put the selector lever on the safe position. Withdraw the takedown pin and replace the sling.

 

VII.    LOADING THE RIFLE

            With the weapon cocked, place the selector lever on SAFE. The magazine may be inserted with the bolt either open or closed; however, you should learn to load with the bolt open. This reduces the possibility of a first-round stoppage and saves the time required to chamber the first round by pulling back the charging handle.

            Open the bolt and lock it open as previously described. Hold the stock of the rifle under the right arm with the right hand grasping the pistol grip, and point the muzzle in a safe direction. With the left hand, insert a loaded magazine into the magazine feedway. Push upward until the magazine catch engages and holds the magazine. Rap the base of the magazine sharply with the heel of the hand to ensure positive retention. Then release the bolt by depressing the upper portion of the bolt catch as previously described. The bolt, as it rides forward, will chamber the top round.

            If you load the rifle with the bolt closed, you chamber the top round by pulling the charging handle fully to the rear and releasing it.

     NOTE:

            Do not "ride" the charging handle forward with the right hand. If the handle is eased forward from the open position, the bolt may fail to lock. If the bolt fails to go fully forward, strike the forward assist assembly (fig. 8-20) with the heel of the right hand.

 

 

Figure 8-21. Locking the bolt open.

 

Figure 8-22. Loading cartridges into the magazine.

 

Figure 8-23. Loading cartridges into magazine with magazine loading strip and charger.

 

 

VII.    Unloading the Rifle

  To unload the rifle and make it safe, place the selector lever on SAFE; press the magazine catch button and remove the magazine; pull the charging handle to the rear; inspect the chamber to ensure it is clear; lock the bolt earner to the rear by depressing the lower portion of the bolt catch; and return the charging handle forward.

   The rifle is clear (and therefore safe) ONLY when no round is in the chamber, the magazine is out, the bolt carrier is to the rear, and the selector lever is on the SAFE setting.

 

IX.     CARE AND Maintenance

    A clean, properly lubricated and maintained M16A1 rifle will function properly and fire accurately when needed. To keep the rifle in good operating condition, you must properly care for it and perform maintenance according to set procedures. Procedures for the care and cleaning of the rifle can be found on the 3-M System's MRCs or in the Army's TM 9-1005-249-10.

    Maintenance of the M16A1 rifle is generally the same as for other small arms previously discussed. The bore and chamber must be kept free of residue and foreign matter. Inspect, while cleaning and lubricating, all sliding or working surfaces for burrs, cracks, or worn areas (repair or replace as necessary) and lubricate with a thin film of lubricant. Remove dirt, rust, grit, gummed oil, and water as these will cause rapid deterioration of the inner mechanism and outer surfaces.

 

 

X–Ray Mechanism of the US Rifle M16A1 Cal. 5.56 mm

 

 

 

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