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Inspection, Cleaning, and Lubrication


AFTER FIRING YOUR 9MM PISTOL or CARBINE, clean it as soon as possible to make the job easier and to avoid allowing the development of any corrosion or rust on steel parts (Carbon Fiber parts - Receivers, etc. - are unaffected by moisture).

WHEN YOUR FIREARM HAS NOT BEEN FIRED, you should clean it at least once or twice a year if you live in a temperate climate, or as often as once a week in a tropical climate.

IF YOU GET YOUR FIREARM WET, clean it as soon as possible to avoid the onset of any corrosion or rust.

Use a high quality rifle cleaning kit that includes a cleaning rod; swab holder; cotton flannel bore patches; a small toothbrush; brass wire bristle bore brush (size appropriate for 9mm caliber) and a Cleaner/Lubricant/Preservative (CLP in Army terminology).




NOTE: The procedures below describe cleaning with a standard military issue multi-piece rod cleaning kit. Other commercial cleaning kits may include alternate cleaning instructions which could be just as effective.

CLEANING THE BORE: The bore of your Bushmaster Firearm has Lands and Grooves called Rifling. Rifling makes the bullet spin very fast as it moves down the Bore and down range. It is difficult to push a new, stiff Bore Brush through the Bore. You will find it much easier, and more effective, to pull your Bore Brush through the Bore. Also, because the brush will clean better if the bristles follow the grooves (this is called tracking), you want the Bore Brush to be allowed to turn as you pull it through.


  1. Attach three Rod Sections together but leave each one about two turns short of being tight. Attach the Patch Holder but leave it two turns short of tight also.
  2. Point Muzzle down. Hold the Upper Receiver in one hand while inserting the end of the Rod with Patch Holder attached into the Chamber. Guide the Rod carefully through the Bore. CAUTION: Do not let the Rod or its threaded end scratch the Rifling in the Bore or the Firing Chamber. About 2 - 3 inches of the Rod should protrude out of the Muzzle.
  3. Attach the Handle Section of the Cleaning Rod to the end of the Rod sticking out of the Muzzle, and swab out the Bore with a patch moistened with “CLP”.
  4. Remove Patch Holder and attach Bore Brush (leaving it two turns short of tight).
  5. Pull the Brush through the Bore and out the Muzzle. You should be able to see the Rod twisting as you pull it - this is the Brush "tracking" in the rifling.
    NEVER reverse the direction of the Bore Brush while it is in the Bore.
  6. After one pull, take off the handle section and repeat the process. After three or four pulls, the three rod sections and the Bore Brush may become screwed tightly together. Loosen them up and repeat the process.
  7. Send a patch through the Bore occasionally to help clean out the crud that the brush is getting loose. Just replace the Bore Brush with the Rod Tip (Patch Holder) and a wet patch. Pull it through. If you leave the rods loose again, the patch will "track" in the rifling as before. But remember, always have the Bore wet with cleaner before trying to pull a brush through.


NOTE: Check to ensure that there is no looseness between the Barrel and the Upper Receiver - if you detect any movement by twisting with your hands, the Barrel Nut must be retorqued. Bring the Firearm to your Gunsmith.

  1. Using a “CLP“ type product, clean all areas (inside and out) of Powder Fouling, Carbon and Dirt.
    Never use a wire brush or any type of abrasive to clean the Upper Receiver - a Toothbrush is good for loosening any dirt buildup.
  2. Clean the Firing Chamber - dip Bore Brush in CLP and use at least 5 plunge strokes and 3 - 360° clockwise rotations. Then swab out the Bore as described previously to remove contaminated solution or loosened crud.
  3. Use a Toothbrush - wet with CLP - to clean carbon and powder residue from inside the Upper Receiver.
  4. Wipe all components clean and dry, and inspect for excessive wear, corrosion or mechanical damage. Contact your Gunsmith to replace any worn or defective parts before firing again (or call Bushmaster at 1-800-998-7928 for parts needs.)


  1. Clean all surfaces of the Bolt with a Toothbrush, Q-Tips or Pipe Cleaners.
  2. Clean and inspect Bolt, Firing Pin, Firing Pin Spring, and Firing Pin Retaining Pin thoroughly.
    CHECK THE BOLT: Look for cracks or fractures. Inspect Bolt Face - Bolts with any pitting extending into the firing pin hole should be replaced.
    CHECK THE FIRING PIN: If it is bent, cracked, too blunted or too sharp, it should be replaced.
    CHECK THE FIRING PIN RETAINING PIN: If it is bent, or badly worn, it should be replaced. Never use a “Cotter Pin” as a substitute for a real Firing Pin Retaining Pin (cotter pins are NOT made of heat treated spring steel, and their round head shape will cause damage).
    CHECK THE EXTRACTOR: If the Extractor is chipped, or has broken edges in the area of the lip that engages the cartridge rim, it should be replaced. Clean off any carbon buildup or powder residue.


  1. Clean all areas of Powder Fouling, Corrosion, and Dirt - don’t use a wire brush or any type of abrasive to clean the Lower Receiver.
  2. Wipe any dirt from the Trigger Mechanism. Carefully clean the Magazine Release Button and the cavity for the Magazine Catch on  the left side of the Receiver. Also inspect and clean the Bolt Catch Mechanism and Receiver’s Takedown and Pivot Pins. Clean the Buffer, Action Spring, and inside the Lower Receiver Extension (the Buffer Tube). A piece of rag attached to the Cleaning Rod and Patch Holder can be used to wipe inside the Buffer Tube. Telescoping Buttstock (on Carbine) may require cleaning as necessary. Telescoping Stock Latch can be pulled down to remove Stock from Receiver Extension Tube.



Lightly Lubricate the inside of Upper Receiver, the Bore and Chamber (using the cleaning rod and a patch), the outer surfaces of the Barrel and Front Sight, and surfaces under the Handguards.


Bolt: Generously lubricate all surfaces of the Bolt - a lighter application is good on the Extractor.


Firing Pin: Lightly lubricate the Firing Pin with CLP - also the Firing Pin recess in the Bolt.

Charging Handle: Lightly lubricate the Charging Handle and it’s Latch and Spring.


Front Sight Detent: Depress Detent and apply two or three drops of CLP to it. Depress the Detent severaI more times to work the
lubricant down into the Spring.



Generously lubricate ALL MOVING PARTS INSIDE THE LOWER RECEIVER including the Trigger, Hammer, Safety, Bolt Catch,  Magazine Release, etc), and their various Pins and Detents. If the firearm is a Full-Auto model, the Auto Sear and Spring will also require lubrication. Don't forget the Takedown and Pivot Pins and their Detents. Use an oiled rag to wipe off fingerprints on exterior surfaces (black cloth is best as it won’t leave visible lint).

Lower Receiver Extension: Lightly lubricate inside the Lower Receiver Extension (the Buffer Tube). Lubricate the Buffer and the Action Spring. Also lightly lubricate the Telestock Latch and exterior of the Receiver Extension.


NOTE: Record how far you move the Rear Sight so it can be returned to its original position upon the completion of this task.

Rear Sight Moving Parts: Use 1 or 2 drops of CLP. Rotate these parts to ensure that the lubricant is spread evenly above, below and around the threads of the Windage Knob / Windage Screw / Detent Hole in Windage Knob / Dual Aperture Flip-up



  1. Insert Action Spring and Buffer (the Spring will lock onto the Buffer if you slide it on - then push and twist counterclockwise). Depress Buffer Detent and push the Buffer in past the Detent, then release Detent.
    NOTE: Carbine Receiver shown here - Pistol is similar.
  2. If you disassembled the Carbine’s Telestock for cleaning / lubrication, re-assembly of Telestock Body onto Extension Tube requires the Telestock Latch be pulled down far enough for its pin to clear the slide track. Check for correct function of all six positions of Telestock.
  3. If the Magazine Well Insert was removed from the Lower Receiver, re-assemble all its components into the left half (which holds the Ejector). Then Screw the right half down onto the left with the Two Socket Head Screws. Re-insert the Magazine Well Insert into the Lower Receiver and carefully re-install the Bolt Catch Spring, Plunger and Bolt Catch. Press down on Bolt Catch components to tension its Spring (this step may require a helper), and carefully re-install the Bolt Catch Roll Pin with a small punch and hammer (again, take care not to damage the Receiver protrusions as you tap this Roll Pin back into place). Then re-install the Magazine Well Front Roll Pin.


  1. Re-insert Firing Pin - with Spring - into Bolt. Push Firing Pin completely into Bolt (you will feel some tension from Spring), then insert Firing Pin Retaining Pin to hold it in place. Check for Spring function, and observe tip of Firing Pin as it protrudes from Bolt face when pushed all the way forward.
  2. Re-insert Charging Handle and Bolt into Upper. With the Upper in an inverted position, the Charging Handle “ears” must drop into cutouts in slot inside the Upper. Then the guide on top of the Bolt can be dropped into the slot in the bottom of the Charging Handle, and both Bolt and Handle can be pushed forward until the Handle Latch locks onto the Upper Receiver.
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