AR-15 Setup and Maintenance – Part 3, by John Smith

(Continued from Part 2. This concludes the article.)

Rifle lubrication / Maintenance

Proper AR-15 lubrication is essential. Everyone usually has their favorite lube of choice. Personally, I started using Lucas Oil Extreme Gun Oil on the outside of the bolt and a homebrew mix of Mobil1 synthetic grease and Mobil1 synthetic oil for the inside of the bolt carrier group (BCG). I went with the Lucas Oil lubricant because they make high performance automotive oils and I trust that they put actual research and testing development into making a high-quality oil that won’t burn off easily from heat. Other small companies may not be able to do as much research and testing. They offer their oil in a small bottle with a syringe type tip that I prefer for oiling.

I got the idea for the Mobil1 homebrew mix from the School the American Rifle channel on Youtube. He uses it because it is relatively cheap compared to name brand gun oils. You mix the synthetic grease with synthetic oil until it is about the consistency of tacky but just starting to drip honey. Use caution on mixing lubricants that may not be compatible with one another. I prefer the Mobil1 mix for inside the BCG because it will probably stay in place longer than straight oil that can be burnt off by the combustion gasses entering inside. Additionally, I believe the Mobil1 mix is probably better for the cam pin-bearing surface to prevent damage.

One of the easiest ways to prevent malfunctions is to ensure that the rifle is properly lubed in the correct places. The main places that you will need to lube will be on the bolt and bolt carrier group (BCG). Ensure all surfaces that make metal-to-metal contact are lubed. On the outside of the BCG, there are two upper “rails,” two lower “rails,” and the bottom that should be lubed. If you are unsure the locations look online or look for where the finish on the BCG is worn. You should also take the bolt out and lube the appropriate surfaces that interface inside the BCG including the gas rings and bearing surface. I use the Mobil1 mix for this job.

Do not under any circumstances lube the bolt face or inside the barrel extension. Lube in these locations could negatively affect the function of your rifle. Once your rifle has some rounds through it, you will most likely be able to see where the friction surfaces are located. For lubrication, I believe the military uses CLP which stands for clean, lubricate, and protect. It works as an all-in-one product. However, in my experience, all-in-one products usually aren’t the best at everything they claim to do. Please note that contrary to popular misconceptions, WD-40 is not a proper lubricant. WD-40 was created to displace water from metal. However, it easily evaporates off the metal and does not provide proper lubrication. One thing I personally do to lubricate the buffer tube is to pull out the spring and buffer and then spray some Teflon lubricant in an aerosol can in the tube. The liquid that comes out of the spray can is a carrier for the Teflon and quickly evaporates.

Proper AR-15 cleaning is essential. First and foremost, always clean the barrel of your gun before firing it for the first time. Heavy oil may be inside the barrel for rust prevention or other foreign debris. This could negatively affect the barrel. Personally, I run a clean patch down the barrel every time before use to ensure any excess oil or even an insect such as a spider is not present. There are two methods of cleaning your barrel. You can either use a traditional cleaning rod or an Otis-style cleaning cable. An Otis-style cleaning cable is sometimes preferable when a gun does not have rear access to the barrel. You can attach a patch or barrel brush to the cable and pull it through the chamber and out the front of the barrel. This method has little chance of damaging the rifle throat or crown. However, I think it is more difficult to get the barrel totally clean because the patch isn’t held as tightly to the inside of the barrel and you can only pull a barrel brush through instead of being able to push it in and out.

Since the rear of the AR-15 barrel is easily accessible, I prefer a cleaning rod with a ball-bearing handle. If the rifle did not have rear access to the barrel for a cleaning rod, you would have to push the cleaning rod from the muzzle to the chamber. This would increase the chances of accidentally wearing the crown of your barrel and reducing accuracy or pushing crud into the action of the rifle (For the M1 Garand, M14, and Ruger 10/22, you can use a Dewey muzzle guard that has a brass bushing incorporated into a Delron jig that attaches to the front of your barrel and guides the cleaning rod preventing it from scraping the rifling and the end of the muzzle).

Luckily, the AR-15 upper can detach from the lower giving easy access to the chamber of the barrel from the rear. When pushing the rod through the barrel, the rod will sometimes flex and cause the rod to scrape on the inside of the barrel. This can be especially bad if the rod scrapes on the beginning or throat of the rifling just after the chamber ends. To prevent this issue, you should buy a Possum Hollow bore guide or similar bore guide. You place the bore guide into the upper receiver and it goes into the chamber of the barrel as well. The bore guide prevents the cleaning rod from flexing and protects the throat of your rifling. This ensures that the beginning of your rifling does not get worn down and cause the bullet to travel a longer free bore distance without being controlled by rifling and preventing premature accuracy degradation. For a normal barrel cleaning, I put a patch on the appropriately sized jag soaked with Bore Tech Eliminator. Then, I run it through the barrel using the bore guide. Sometimes I run two wet patches through. Let the barrel sit for 5 mins or so and then put on the appropriately sized brush.

While using the bore guide, run the brush from the rear of the barrel to the muzzle. Just barely allow the brush to come out of the barrel and carefully reverse the cleaning rod so that the rod does not contact the crown or rifling at the end of the muzzle. It is important that you do not inadvertently scrape the rifling at the muzzle and negatively affect accuracy. Make 6-10 strokes with the barrel brush depending on how dirty it is. Then, I run another patch on a jag soaked in the Hoppe’s No. 9 to clean out the crud. Wait another 5 mins or so and then run a dry patch to see how it looks. Usually, I run a few more dry patches until they come out pretty clean. If you are going to store the rifle for a long period of time, I put a few drops of oil on a patch and then run it through.

AR-15 Spare Parts

You will need a few spare parts to maintain your rifle and ensure that it continues functioning properly. With the relatively cheap cost of around $100, you should pick up a spare BCG. Keep in mind you should check headspace if you plan on using the bolt in your rifle. The spare BCG can act as a total drop-in replacement should anything break on your original BCG or you can use if for spare parts. The spare BCG could be a quick field swap if yours malfunctions while in use. A great spare part kit is the Bravo Company SOPMOD bolt upgrade/rebuild kit that can be found on Brownells. The part kit includes a spare extractor, chrome silica extractor spring, extractor rubber ring and insert, and gas rings. Chrome silica springs last longer than the USGI specification springs for both the extractor and ejector. According to the Youtube channel School of the American Rifle everyone should change their extractor spring to a Sprinco 4-coil chrome silica spring to reduce the chances of one of the most common gun malfunctions: failure to extract. It is also suggested that the ejector spring be upgraded to chrome silica, but it is not as critical as the extractor spring. Unfortunately, if you want to change out the ejector spring, you most likely will need a bolt vise similar to the Sinclair model and it will cost a little over $30 or a Real Avid master bench block. Make sure to add a spare firing pin to your list. Additionally, may need a new buffer spring after a few thousand rounds.

I hope that the information presented here has led you to become more informed on AR-15 configurations, parts, and how to take care of your rifle. It is amazing that there are so many things to consider while determining the best configuration for your situation.