Bolt Carrier Group Breakdown
Hey guy's I appologize in advance for this somewhat nooby question, what is the best way to clean the AR15 bolt carrier group? I have yet to take it completely apart, I've sprayed solvent in there, as well as cleaned it really well with Q-Tips and rags, but after I rack a round into the chamber I'm still seeing some black material on and around the primer, is it nessecary to take the entire bolt carrier apart after shooting, or is there a simplier way to get it cleaned after every use? I'm honestly a little weary about taking it completely apart, fearing I might lose a spring or other component during the break down. Is there a good step by step guide that you guys would recommend going over as you're taking it apart?
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Stay away from U TUBE! Some of those folks are deranged, IMHO. Brownells has excellent on-line videos on maintaining and building AR's. 0 -
First:DO NOT DISASSEMBLE THE GAS KEY FROM THE BOLT CARRIER!!
Otherwise, the basic disassembly involves pulling the firing pin retainer(cotter key)and shaking the firing pin out the back of the bolt carrier. Push the bolt back into the carrier and turn the cam pin 90* and pull it out past the gas key. Pull the bolt out the front of the carrier.
I have a tall skinny container that will hold the carrier front end down so it can soak. Another smaller container holds the bolt, FP, and cotter pin. After soaking, just wipe the parts with rags unless you've done a lot of shooting in which case, some scrubbing with a bristle brush may be needed. Up to this point, I've not found it necessary (or prudent) to remove the extractor or ejector.
A relative with 2 tours in Iraq commented that none of the troops were allowed to disassemble the BCG further than what I've described. Their M-4's bolts didn't require more cleaning than this even when used for high volumes of full auto fire. They did frequently use a carbon scraper on the inside of the carrier and tail of the bolt.0 -
No need to worry.
Basic disassembly of the BCG for cleaning is very simple and straightforward, with a minimal number of parts. Keep in mind that this design can be disassembled/reassembled in the dark.
There are no springs or tiny parts to lose. In fact, the only spring you're seeing on a diagram (extractor spring) remains attached to the extractor after this component is removed.0 -
TIP: To make BCG disassembly easier, go to the surplus store and buy a stainless dentists pick. File off the sharp points, making it have a bit of a rounded or flat end. This makes pushing out the extractor pin easier, and the hook is used to remove the cotter pin holding the firing pin in place. NEVER force anything, it should all go together fairly easily. If not, check to make sure you're all lined up before you try forcing anything.
Easy extra basic BCG cleaning step by step:
Remove BCG. Pull cotter pin, wipe down and set aside on mat. Tilt BCG and slide out firing pin. Wipe off, set on mat. Push bolt back into carrier a bit, turn the cam pin 90 degrees so it clears the gas key, then remove. Wipe down, set on mat. Remove bolt by pulling it out of the carrier. Do a little "pinch" on the extractor, then use dentists pick to push extractor pin from bolt and remove extractor. (Without the "pinch" it's held tightly by friction) Wipe pin, set on mat. Wipe extractor, examine for cracks/damage, spring condition, etc. If OK, set on mat. Wipe bolt, check gas rings for wear, lugs for cracks, etc. Run pipe cleaner through center. If all OK, set on mat. Wipe down bolt carrier. I'll occasionally run a patch carefully thorough the inside using a coated rod and plastic jag so it won't scratch the metal. I'll then use pipe cleaner to clean inside the gas key as well. (I do not push out the ejector pin and go through all of that, but some may go to this extreme. I'll use the dentists pick to push it in and ensure it's moving on occasion)
This is about all you'll need to do, as the guns will run when filthy if properly lubricated. (Google "Filthy 14" for an example. A BCM 16" mid-length going 40,000+ rounds without the BCG being cleaned every time, just lubed and broken bolt parts replaced when needed.) Pat Rogers at EAG Tacitcal regularly runs their loaner guns to 5,10,even 15 rounds without a BCG "cleaning", he just keeps them lubed up.
If your bolt gets built-up carbon on it that you just have to remove, soak it for a while in a carbon cutter then use a stiff nylon brush to scrub it down. I do not recommend using a metal brush or the pick to scrape the carbon off, you do not want to score this part up.
If rings are worn, replace them. It's easy to do. Personally I use the one-piece ring sets Brownells sells. These have yet to wear, and don't need to be "aligned" in a staggered pattern. (Some aren't staggering the alignment anymore, I still do on guns with the 3 rings) Same for extractor springs. I use the stiff spring with the nylon donut; since then no FTE jams.
Reassemble in reverse order after lubrication. The extractor takes a bit of a "pinch" to line up the holes, once it is the pin just drops in.
I use Slip2000EWL on my guns, it's some dang good stuff. Remember; put the firing pin in and make sure it's all the way in the BCG BEFORE the cotter pin is replaced. (Tilt it back and slap it lightly on your palm, if it falls out re-do it correctly) If not, it'll sit too far back, will not fire, and will ultimately bend and jam up the gun when fired or slammed about with the charging handle. (On a quick inspection, I found one M-4 put together incorrectly by the shooter in this manner this past week.)
This is not gosphel, there are lots of other steps that others may use which are perfectly acceptable; I just found this little routine works for me maintaining my Ar-15 collection and the ones I keep running for others. Caveat emptor on You Tube. Some dudes are good. Some so-so. And some are really Bubbas with a digital camera.0 -
As folks have said before, it's pretty simple. There are three "tiny" parts that can easily be lost so remember how you put them down. As riomouse said USE A ROUTINE when cleaning these and it will be no problem.
The three 'tiny' parts are the cotter pin, the extractor and extractor pin. The cam pin and firing pin aren't all that big either and can get lost in a fold of clothing so be careful when using your body as a place to put the parts if having to clean in the field.
I push out the rear takedown pin. Then I remove the charging handle and BCG. Lay the rifle down and begin separating the BCG parts. Pull the cotter pin, wipe it, set it down on a rag next to the carrier. Remove the firing pin, wipe it, set it down. Turn and remove the cam pin. Wipe and set. Remove the bolt. Use the firing pin to push out the extractor pin. Wipe down all of the outside and set down, with the exception of the bolt. I use a pipe cleaner to get in the inside channel for the firing pin. You can also hose this out with brake cleaner or CLP. If using any oil product, just be sure clean afterwards. Immediately reassemble the bolt.
Now take the BCG and wipe the outside down. I then take a .30 cal brush wrapped with a shotgun patch or small piece of rag. I wrap the rag/patch around the .30 cal brush (mounted to a cleaning rod) and push it through the BCG. Ball it up and wipe out the ends. You want to wipe all the carbon away. You especially want to get the cam slot clean. Once that is clean reassemble the BCG.
Use a solvent to loosen carbon/crud in the reciever. Wipe out the receiver. Take a Q-tip and wipe around the barrel extension inside the receiver. Use a bore brush to loosen the crud in the chamber. Wrap a small rag piece around the bore brush and wipe out the chamber. If you can get them you can also finish cleaning the chamber with a mop. Clean the barrel of the rifle, patching from breech to muzzle. I use bore foam and let it sit for a little while before running patches down the bore. Wipe any other odds and ends and reassemble wiped down BCG and charging handle back into shotgunned AR. Do a quick function test and you are ready to rock-n-roll again.0
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