How to clean/lube your BCG

The bolt carrier group (BCG) is the heart of your AR15.  It is one of the most critical components to function and regular field maintenance requires some special care to help ensure it has what it needs to keep your AR15 running up to par.

When you clean your BCG is dependent on the firing schedule, environment, and many other factors. However, what it all boils down to is preventative maintenance. By taking a short amount of time to quickly clean and lubricate your BCG, you help minimize the risk of your firearm experiencing issues in the field or on the range. Cleaning is important and proper lubrication is paramount.

These methods are in no way shape or form the one single way to clean and lubricate a BCG. This is a simple, easy way to help keep your gun running right without going into a full “white glove” clean. Generally speaking the more frequently you clean your bolt carrier group, the easier it is to clean as it will stop a lot of hard carbon buildup before it happens.

Lubrication will need to be assessed on a case-by-case basis. Environmental factors such as temperature, humidity, and airborne contaminants all play a part in choosing an effective lubrication method. You should always test your lubricant in the environments that the firearm will be used to ensure proper function.

Here is a list of general gun cleaning items that will be helpful for this:

• Firearms grade solvent (Ensure that the solvent you use is safe on your firearm and its components finishes, Hoppes #9 is GENERALLY safe in most applications).
• Cleaning patches
• Brass brush
• Nylon brush
• Cotton swabs
• Firearms lubricant (see above statement on lubricant).

With all that out of the way, we can get into cleaning. Before we start scrubbing away all that dirt and grime, you will need to field disassemble your bolt carrier group. To disassemble your bolt carrier group complete the following steps.

1. Remove the firing pin retaining pin from the bolt carrier by grabbing the looped end and pulling it outwards. This may require needle nose pliers or a small, pointed tool.
2. Turn the bolt carrier group so that the carrier is facing your working surface. If the firing pin does not freely fall out of the carrier, lightly tap the rear of the carrier on your working surface until the firing pin falls free.
3. Rotate the cam-pin 90 degrees and remove it from the carrier (the bolt must be collapsed into the rearward position inside the carrier for this step).
4. Remove the bolt from the carrier.

With disassembly out of the way. We can dive into cleaning. To start, you can give each component a thorough wipe-down with a lint-free rag. This will remove most of the soft carbon from the exterior of the components. From here you will want to identify any hard buildup of copper, carbon, or other mysterious substances that may have found their way onto your bolt carrier group. To remove any hard-to-clean buildup you will want to use a combination of solvent and cleaning tools. A nylon brush will generally take care of any buildup.

Remember, your BCG does not need to be spotless. I know this may feel wrong, but they are tools designed to run in adverse conditions. A little bit of leftover carbon won’t hurt anyone (this is especially true with the tail of your bolt, this area will accumulate hard carbon, but generally this is a non-issue).

The inside of your carrier and the bolt lugs may require some special care to get all the way clean. For these hard-to-reach areas, cotton swabs may be helpful to remove any carbon fouling. Do take care to not leave any cotton behind on the inside of your carrier and avoid using them in areas like your gas key or the inside of your bolt tail. 

Lastly, one area I like to give special care to is the front of my bolt. You will want to ensure that this region is free and clear of any dirt or debris.

Before we move on to reassembly and lubrication, you will want to ensure that any solvent has been wiped off the bolt carrier group components. Solvents and lubricants (generally) don’t play well together, so applying lube to a solvent-covered part is not advisable.

You can assemble and lubricate at the same time or lubricate when you are done. There are some areas I like to lubricate that is not easily accessible while the bolt carrier group is assembled (such as the bolt body), so you may want to apply lubrication during assembly.

To reassemble your bolt carrier group, complete the following steps:

1. Insert the bolt into the carrier fully ensuring that the cam pin channel in the bolt is aligned with the cam pin channel in the carrier. The cam pin channel is a through hole on the bolt and is uni-directional, so make sure your extractor is facing the ejection port side of the carrier.
2. Insert the cam pin into the cam pin channel and rotate it 90 degrees.
3. Feed the firing pin into place and ensure it is fully seated inside the carrier.
4. Insert the firing pin retaining pin into the carrier taking care not to use excessive force (this can result in damage to the retaining pin).

Lastly, these are some areas I generally apply lubrication in most circumstances. These are as follows:

• Bolt carrier rails (these are the friction surfaces where your bolt carrier contacts the inside of your upper receiver)
• Bolt lugs (take care not to lubricate the face of your bolt).
• Bolt Body
• Cam pin channel (I apply a generous amount here)
• Bottom of Carrier

Within reason, it is impossible to over-lubricate an AR15 in most circumstances. Use a reasonable amount but don’t be shy. Not enough lubrication is much more likely to cause a problem than too much.

With your bolt carrier cleaned and lubricated, it is ready to be re-installed in your firearm to get dirty again. Remember, this is preventative maintenance and the more frequently you do it the less likely you are to have issues in between deep cleans.