1. Disassembling Your Rifle
To prepare your AR for cleaning, basic disassembly or 'œfield-stripping' is necessary. After double-checking to make sure the firearm is unloaded, prepare a suitable flat surface, such as a workbench or countertop. As you'™ll be dealing with several small parts that can get lost, you'™ll want a small plastic tub or at least a towel available.
2. Separate the Receivers
The first step to cleaning your AR is separating the receivers. You can totally separate the upper and lower receivers for cleaning, but I prefer to leave them linked — at least initially. Begin by pressing the rear takedown pin from left to right to release the upper and lower receivers. Hinge the upper forward and up, then pull the charging handle to the rear, which will allow you to remove the bolt carrier from the upper. Slide the charging handle to the rear while pressing downward and it will release from the upper. Use the nose of the charging handle to depress the buffer retainer on the lower receiver (Note: The buffer is under spring pressure) and remove the buffer and spring. Your rifle has now been broken-down into the major sub-assemblies.
3. Bolt Carrier Disassembly
Now it'™s time to strip the bolt carrier assembly. Press the bolt fully rearward into the carrier and — using an object such as a ballpoint pen — push the firing pin retaining pin until you can remove it with your fingers. Remove the firing pin from the assembly; it may fall out if you turn the bolt upward. Rotate the cam pin 90 degrees and remove it from the bolt. The bolt can now be removed from the carrier. Using the firing pin as a punch, push the extractor pin out of the bolt and remove the extractor. Your rifle is now fully field-stripped and ready for cleaning.
4. Chamber Cleaning
If you'™ve fired your rifle much, you'™ll notice most of the interior is coated with greasy, black carbon residue from the gas system. Sooner or later, that fouling must be removed or it will gum-up the works and disrupt the function of the firearm. There are two main methods of removing this carbon: the traditional method of scrubbing each of the parts with powder solvent and a toothbrush or cloth, or using an aerosol product like Gun Scrubber
or Powder Blast
to quickly remove most of the carbon buildup. If you don'™t mind the mess and have a suitable location available, the aerosol method will save you time and elbow grease. Be careful not to lose small parts such as the extractor pin when cleaning them.
Whichever method you choose, it is important to ensure all of the fouling is removed from the internals; anything with carbon or other crud should be completely cleaned. Because an AR uses propellant gases to cycle the action, you'™ll likely find a heavy buildup on the tail of the bolt and on the inside of the colt carrier, which can be stubborn to remove. Special products such as Magna-Matic'™s Carbon Removal Tool and A&O Manufacturing'™s Bolt Carrier Carbon Scraper are designed specifically for removing carbon buildup from those areas and can save lots of time and foul language.
5. Cleaning the Bolt Lug Recess Area
Another area of special concern is the bolt lug recess area. The AR uses eight rectangular locking lugs on the bolt to hold the cartridge in-battery. The area where these lugs interface with the barrel extension can accumulate significant debris. It is imperative that you clean this area thoroughly in order to keep the rifle functioning reliably. An AR chamber brush is a key piece of cleaning equipment for any AR owner; get yourself a few in case one gets lost or worn. The brush has two different diameter bronze bristles: The narrower section cleans the rifle'™s chamber while the larger brush scrubs the locking lug recesses. Wet the brush with cleaning solvent — or spray the area with your aerosol cleaner — and rotate the brush to loosen caked-on debris. You'™ll want to give the chamber area extra attention if you'™ve used steel-cased ammo, as it commonly leaves lacquer or polymer residue on the chamber walls. Once this area has been thoroughly brushed, use a large handgun-sized cloth patch on a short rod to remove the dirty solvent and give it a final scrubbing.
6. Bore Cleaning
Now it'™s time to clean the bore. Removing powder and copper fouling from the bore of an AR is no different than cleaning any other rifle, except the two-piece receiver design can make things a bit trickier. My preference is to clamp the rifle into a cleaning cradle and to use a Sinclair Cleaning Link
, which separates and holds the upper and lower assemblies to provide you access to the bore. A rod guide keeps the cleaning rod aligned with the bore and prevents solvent from draining into the rifle'™s lower. Any common bore solvent will work, simply follow the product'™s instructions until you'™re satisfied that the bore is suitably clean.
7. Inspection and Lubrication
With the rifle clean, now is an ideal opportunity to inspect the rifle and its components for worn, cracked or broken parts. Some parts on the AR wear faster than others, and it'™s important to keep track of wear so that parts can be replaced before they break. Pay particular attention to the bolt. Look for hairline cracks where the cam pin enters the body of the bolt, as that is usually where breakage occurs. The locking lugs should also be inspected for cracks or other imperfections. While you are inspecting the bolt, ensure the three gas rings are not aligned — their slots should all be in different locations to ensure a tight gas seal. Take a look at the bolt carrier and ensure the gas key fits tightly and that the screws are staked into place so they cannot rotate. Any parts that are suspect should be taken to an armorer or gunsmith, or should be replaced.
With the rifle clean and inspected, it needs to be lubed before reassembly. Semi-auto rifles require more lubrication than most other firearms, so don'™t skimp on the lube. I use lithium grease because it doesn'™t migrate when hot, but any gun oil will work. Your rifle will tell you where to apply lube since those areas will have their finish worn from friction. The outside of the bolt body, bolt locking lugs and the four longitudinal ridges on the bolt carrier are key lubrication points on the AR. Conversely, I avoid using lube in the firing pin channel or on the trigger parts.
Proper cleaning and maintenance are key to keeping your AR running reliably. If you take care of your AR, clean it regularly and feed it good ammo, it will provide many decades of good service.